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AN INVESTIGATION INTO PET PLASTICS AND PET RECYCLING:
Name
Instructor’s name
Course
Date
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Table of Contents:
1.1 Abstract…………………………………………………. 4
2.1 Introduction…………………………………………….. 5
3.1 Literature review……………………………………….. 8
4.1 Background Information……………………………….16
4.1.1 Research questions and Hypotheses………………….18
4.2 Methodology…………………………………………...19
5.1 Results………………………………………………….20
6.1 Discussion………………………………………………30
7.1 Conclusion………………………………………………34
8.1 Recommendations……………………………………….36
9.1 References……………………………………………….40
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Commonly used terms and abbreviations:
PET - Polyethylene Terephthalate
HDPE- High-Density Polyethylene:
PVC- Polyvinyl chloride:
LDPE- Low-Density Polyethylene:
DMT- Di Methelene Terephthalate.
PP- Polypropylene.
PS- Polystyrene
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1.1Abstract:
The project is about the PET plastics and PET recycling. This is a process of recycling
plastics that are recyclable from the environment. PET is a thermoplastic polymer resin
belonging to the polyester family. It is basically used in the manufacture of synthetic
fibres, food and beverage liquid containers. Other uses include the thermoforming
applications and the engineering resins where it is often mixed with glass fibre.
On the methodology, research has shown that mixing starch with plastic will lower
degradation, but it still doesn't lead to complete breakdown of the plastic. Bacteria have
been genetically engineered to synthesize a completely biodegradable plastic, but this
material is expensive at present.
Recycling of plastics reduces the trash deposited in landfills, and offers the opportunity
for consumers to clean and reuse containers for everything from water spritzer bottles to
holding excess amounts of shampoos, cleaning fluids or lotions. Recycling all plastic
bottles that contain PET or HDPE labels somewhere on the bottle, most often found on
the neck of the bottle to make separation of recyclable and non-recyclable plastic easier
on consumers is a better remedy.
It is recommended that the current bottle bills should also be expanded even to other
countries. In 2005, 2 million tons of plastic bottles in the United States ended up in the
trash instead of in recycling bins. The State container deposit law which is known as
"bottle bills" are long overdue for an upgrade. They have proven to be the most effective
approach to collecting bottles and cans. Currently, only 11 states have bottle bills in
America.
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2.1 Introduction:
Plastics are indeed everywhere, from the grocery to the shopping mall. They are
important in the packaging industry, but a closer look at the plastics brings into focus the
price to be paid by using and dumping it the wrong way. This therefore calls for a lot of
care. Before you toss that plastic bag to the environment then be sure of the impact you
are creating. Plastics are very durable and this means that they will degrade very slowly
therefore takes long in the environment. Decomposition by burning also creates serious
toxic fumes in the atmosphere. The production as well takes significant amount of fossil
fuels which pollutes the environment (Tukker, 2002). Several plastic debris remains
floating on the sea surface and this creates danger to the marine life. Most sea animals
have died due to the ingestion of plastic materials. Solar radiation degrades plastics into
smaller particles which eventually becomes plastic dust and goes to pollute the
atmosphere.
The acronym PET stands for Polyethylene terephthalate. This is a thermoplastic polymer
resin belonging to the polyester family. It is basically used in the manufacture of
synthetic fibres, food and beverage liquid containers. Other uses include the
thermoforming applications and the engineering resins where it is often mixed with glass
fibre. The monomer can be processed in several ways and these include: The
esterification of terephthalic acid and ethylene glycol with water as the by product. It can
also be synthesized through transesterification of ethylene glycol and dimethyl
terephthalate with methanol as the by product. Finally it can be polymerized through
polycondensation of the monomers with water as the by product.PET is commonly
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referred to as polyester and is the third most abundant plastic production behind
polyethylene and poly propylene (Tierney & John 2006). It is widely used in the
production of synthetic fibres.
Due to this damage to the environment, it is therefore imperative to develop ways of
recycling the plastics and this brings us to the actual project that is PET plastics and PET
recycling. The objective of the project is basically to reduce plastics in the environment
through recycling. It also aims at developing appropriate measures to deal with the plastic
menace. The project also focuses on achieving a clean environment which is safe to live
in. It also aims at fostering recycling of plastics as the best option to keep them off the
environment.
The recycling processes with polyester are as varied as the manufacturing processes
based on primary pellets. Polyester can be used today in most of the polyester
manufacturing processes as blend with virgin polymer or increasingly as 100% recycled
polymer. This will depend on the purity of the recycled materials. There are some
exceptions like BOPET-film of low thickness, special applications like optical film or
yarns through FDY-spinning at > 6000 m/min or microfilaments and micro-fibers that are
produced from virgin polyester only.
There exist a number of internal recycling processes where fibre is reused directly to
produce fibre and the same to both performs and films. In a nut shell the following
general simple procedure is used in the process. First is the bale opening then followed by
the sorting and selection for different colours, foreign polymers. Next is the pre-washing
without cutting before the cutting process. Stones are then removed and other debris like
6
glass and metal. Air sifting is done to remove film paper and labels. It is then ground and
low density polymers removed. Hot wash is done followed by caustic wash to maintain
intrinsic viscosity. After which the rinsing is done twice. It is then dried and followed by
air sifting flakes before sorting the flakes automatically. Water circuit and water
treatment technology is then employed to attain flake quality.
There exist some defects which are encountered during the process. They can be grouped
into several categories. The reactive polyester –OH or –COOH end groups could be
transformed into non reactive end groups like the formation of vinyl ester end group. The
end group could also shift towards the direction of the –COOH end groups. This would
be due to build up during thermal and oxidative degradation. The number of poly-
functional macromolecules could also increase. The number, variety and concentration of
non- polymer identical organic and inorganic compounds may increase.
They can be detected either chemically or physically through the following processes.
Increase of –COOH end group, increase of color number B, increase of oligomer content,
reduction in filterability, increase of by products like acetaldehyde, increase of
extractable foreign contaminants, decrease in colour L, decrease ofl intrinsic viscosity,
decrease of crystallization temperature and increase in crystallization speed, decrease in
mechanical properties like tensile strength, broadening of molecular weight distribution.
The statement of the problem to the project states that although plastics are very
important to the users, proper disposal through recycling is required to avoid massive
environmental degradation.
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3.1 Literature Review:
Plastics have a major impact in the society due to poor disposal. Most marine lives,
human lives and even the terrestrial animals’ lives have been lost due to this menace of
plastics. This therefore calls for the appropriate measures to curtail the problem. The
most appropriate method is then use of then recycling technology to keep the plastic
materials out of the environment.
On the other hand there are scholars who claim the benefits of plastic materials outweigh
their negative impact to the environment (Thomas & Visakh 2011). Some of the benefits
floated include: In electronics, laptops could not function well in case they were made
from glass. Plastics are used in building and construction as a cheaper material as
compared to the others. They are indeed very useful in the packaging industry. Plastics
have slowly taken over the normal paper in the packaging industry. Plastics are very
durable and their manufacture is very cheap. It can as well be recycled rather
decomposing it. This can be achieved easily than producing a new one. Plastics can be
reused over and over again as opposed to the aluminum materials. They do not corrode as
does with the metals. They are not breakable as with the glass materials. Plastics are light
in weight and are usually odourless and thus can be used to carry most things.
PET is an acronym that stands for Polyethylene terephthalate. This is a thermoplastic
polymer resin belonging to the polyester family. It is basically used in the manufacture of
synthetic fibres, food and beverage liquid containers. Other uses include the
thermoforming applications and the engineering resins where it is often mixed with glass
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fibre. The monomer can be processed in several ways and these include: The
esterification of terephthalic acid and ethylene glycol with water as the by product. It can
also be synthesized through transesterification of ethylene glycol and dimethyl
terephthalate with methanol as the by product. Finally it can be polymerized through
polycondensation of the monomers with water as the by product.PET is commonly
referred to as polyester and is the third most abundant plastic production behind
polyethylene and poly propylene. It is widely used in the production of synthetic fibres.
Due to the addition of polyvinyl alcohol, there is a reduction in oxygen permeability.
PET is considered an excellent barrier material as some health practitioners use gloves
made of this material. It is usually used in tape applications like in the carrier for
magnetic tape or the backing for pressure sensitive adhesive tapes due to its high
mechanical strength. Thermoformed PET can be used in the storage of frozen dinners.
This is because of their ability to withstand extreme temperatures. Nylon is a product of
PET. It is naturally strong with high strength and ability to form several products. PET
has a variable intrinsic viscosity range.
The process of manufacturing PET takes distinct stages. The initial stage is the Drying
stage. This is achieved since PET is hygroscopic. Drying is achieved by the use a
desiccant. This is basically achieved by the passage of a series of hot air through the
material. It can also be done by the use compressed air. The next stage is the modification
through copolymerization. An example is where the melting point can be lowered
through the addition of cyclohexane dimethanol. Copolymerization is very important in
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the thermoforming and in the crystallization process like the material used in the seat
belts. Crystallization of polymers occurs when a polymer chains fold to form some
repeating pattern.
PET is considered a semi-crystalline polymer since only 40% of the polymer is
amorphous. The solid state crystallization is a process in which PET is crystallized to
glass like substance through a very rapid cooling process. For the process to make
effectively, a catalyst must be employed in the form of Antimony trioxide (Sb2O3).
Exposing PET to boiling or microwave could increase levels of antimony. This could be
detrimental to the health status of individuals who consume products packaged with such
material. Environmental Health Perspectives in April 2010 claims that PET might yield
endocrine disruptions. Contrary to this Franz and Welle gave evidence based on
mathematical modeling claiming that PET is unlikely to yield endocrine disruptions when
consumed in mineral water.
The degradation process of PET takes different forms like the hydrolytic, thermal
oxidation and the thermal which is the most important. This degradation process leads to
discolouration, chain scissions due to reduced molecular weight and the formation of
other products like the acetaldehyde and crosslinks. This interferes with the optimal
requirements especially in the packaging industry. The best way to alleviate this menace
is through the use of copolymers. These will lower the melting point and reduce the
degree of its crystallinity. The use of stabilizers like phosphites which are mainly
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antioxidants can also stabilize the polymer. Acetaldehyde can cause foul taste in bottled
water when formed onto the walls of the container.
There are two ways employed in the recycling of PET. They are the chemical and the
mechanical. The chemical process destroys all the structure thereby forming new
intermediates like cis-ß-hydroxyterephthalate. In mechanical recycling, the original
properties of the polymer are being maintained. Chemical recycling comes in handy
when large tones of the product are needed within a very short time. Mechanical
recycling is used in small and medium scale industries. Apart from the general
contaminants from the first stage of formation, mechanical impurities depreciate the
quality of the recycling process. This calls for efficient sorting, cleaning and separation
process in order to attain optimum results.
The industry consists of three major sections: The Waste Logistics section where
collection and separation of wastes is done (Porter, 2002). The Flake production section
where clean bottles are produced. The Flake Processing section where PET flakes are
converted to final products. There exist a number of internal recycling processes where
fibre is reused directly to produce fibre and the same to both performs and films. In a nut
shell the following general simple procedure is used in the process. First is the bale
opening then followed by the sorting and selection for different colours, foreign
polymers? Next is the pre-washing without cutting before the cutting process. Stones are
then removed and other debris like glass and metal. Air sifting is done to remove film
paper and labels. It is then ground and low density polymers removed. Hot wash is done
11
followed by caustic wash to maintain intrinsic viscosity. After which the rinsing is done
twice. It is then dried and followed by air sifting flakes before sorting the flakes
automatically. Water circuit and water treatment technology is then employed to attain
flake quality.
The defects encountered during the process can be grouped into several categories. The
reactive polyester –OH or –COOH end groups could be transformed into non reactive
end groups like the formation of vinyl ester end group. The end group could also shift
towards the direction of the –COOH end groups. This would be due to build up during
thermal and oxidative degradation. The number of poly-functional macromolecules could
also increase. The number, variety and concentration of non- polymer identical organic
and inorganic compounds may increase.
These can be detected chemically or physically through the following processes. Increase
of –COOH end group, increase of color number B, increase of oligomer content,
reduction in filterability, increase of by products like acetaldehyde, increase of
extractable foreign contaminants, decrease in color L, decrease of intrinsic viscosity,
decrease of crystallization temperature and increase in crystallization speed, decrease in
mechanical properties like tensile strength, broadening of molecular weight distribution.
There are several examples for processing polyester. The recycling processes with
polyester are as varied as the manufacturing processes based on primary pellets. Polyester
can be used today in most of the polyester manufacturing processes as blend with virgin
polymer or increasingly as 100% recycled polymer. This will depend on the purity of the
recycled materials. There are some exceptions like BOPET-film of low thickness, special
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applications like optical film or yarns -spinning at > 6000 m/min or microfilaments and
micro-fibers that are produced from virgin polyester only.
The processes include simple re-pelletizing of bottle waste into flakes. This involves
transforming bottle waste into flakes, by drying and crystallizing the flakes, by
plasticizing and filtering, as well as by pelletizing. The product is an amorphous re-
granulate of an intrinsic viscosity in the range of 0.55–0.7 dl/g, depending on how
complete pre-drying of PET flakes has been done. They have to be crystallized and dried
before further processing. Processing is done in order to obtain the following a PET film
for thermoforming, addition of PET virgin production, packaging film, PET bottle resin
by SSP, Carpet yearn, Engineering plastic, Filaments, Non woven materials, Packaging
stripes, Stable fibre. By selecting the re-pelletizing way means having an additional
conversion process which is at the one side energy intensive, causes thermal destruction
and cost consuming. On the contrary, pelletizing step is providing the following
advantages: intensive melt filtration, intermediate quality control, modification by
additives, product selection and separation by quality, increased processing flexibility,
and quality uniformity.
The other process is the manufacture of PET pellets or flakes for bottles. This is a bottle
to bottle process. It is similar to the one described above in principle; however, pellets are
directly crystallized and then subjected to a solid-state polycondensation (SSP) in a
tumbling drier or a vertical tube reactor (Piringer, 2000). The corresponding intrinsic
viscosity of 0.80 – 0.085 dl/g is re build again and, at the same time, the acetaldehyde
content is reduced to 1 ppm in this process. Besides its’ approval it is nevertheless
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important that any user of such processes has to constantly check the limits for the raw
materials manufactured by himself for the process.
There is also the direct conversion of bottle flakes. This is done to minimize costs.
Polyester intermediate producers like spinning mills, strapping mills or cast film mills are
working on the direct use of the PET-flakes, from the treatment of used bottles, with a
view to manufacturing an increasing number of polyester intermediates. It is possibly
necessary to reconstitute the viscosity through polycondensation in the melt phase or
solid-state polycondensation of the flakes in order to adjust the viscosity. The application
of twin screw extruders, multi-screw extruders or multi-rotation systems and coincidental
vacuum degassing to remove moisture and avoid flake pre-drying are indeed the current
PET flake conversion processes. They allow the conversion of non-dried PET flakes
without substantial viscosity decrease caused by hydrolysis. About 70% is of PET bottle
flakes are converted to fibers and filaments.
In direct secondary materials such as bottle flakes in spinning processes, there are a few
processing principles to obtain. The first being the high speed spinning process for the
manufacture of POY. This needs a viscosity of 0.62–0.64 dl/g. The viscosity can be set
via the degree of drying beginning from the bottle flakes. For full dull or semi dull yarn
the use of TiO2 must be added. An efficient filtration of the melt is necessary for the
protection of spinnerets. Staple fibres may also be spun in an intrinsic viscosity range
which lies lower and which should be between 0.58 to 0.62 dl/g. The viscosity can be
adjusted via drying or vacuum adjustment in case of vacuum extrusion. However, the
addition of chain length modifiers like ethylene glycol or diethylene glycol may be used.
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The basic spinning non-woven in the field for textile applications as well as heavy
spinning non-woven as basic materials, for example in roof covers or in road building
where it can be manufactured by spinning bottle flakes. The spinning viscosity is again
within a range of 0.58–0.65 dl/g. The manufacture of high tenacity packaging stripes and
monofilaments is another area of great interest. The initial raw material is a recycled
material of higher intrinsic viscosity. The monofilaments as well as the high tenacity
packaging stripes are then manufactured in the melt spinning process.
The recycling of PET back to the initial raw materials takes three major processes. The
first one being the glycolysis or partial glycolysis process. The polyester is transformed
into an oligomer by adding ethylene glycol or other glycols during thermal treatment. The
advantage of this process is the possibility of separating the mechanical deposits directly
and efficient through a progressive and stepwise filtration (Mantia, 2002). The decisive
effect on the quality of the end product depends on the filteration finess of the last step.
This demonstrates how bottle waste can successfully be recycled in a continuously
operating polyester line. The quality of the bottle pellets which are manufactured on the
line are maintained with 10-25% bottle flakes feeding into the processor.
Temperature is brought to the lowest possible limit. The possibility of a chemical
decomposition of the hydro peroxides is possible by adding a corresponding P-stabilizer
directly when plasticizing. Treatment by adding H3PO3 in the last step helps in the
destruction of hydro peroxide groups. The finely filtered recycled and partially
glycolyzed material is continuously fed to the esterification or prepolycondensation
reactor. Dosing quantities are adjusted accordingly. Japan has used the treatment of waste
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through total glycolysis to convert polyester to Cis-B hydroxyl-terephthalate in
experimental production.
The next process is through hydrolysis which operates under very high pressures and
supercritical conditions. PET-waste is directly hydrolyzed for example by applying
supercritical water steam. Re-crystallization in acetic acid will help in the purification of
crude terephthalic acid.
The final process is the methanolysis which is basically for the large scale production.
Polyester waste is transformed with methanol into DMT, under pressure and in presence
of catalysts. Filtration of the methanolysis product is then applied. Crude DMT is finally
purified by vacuum distillation. Methanolysis is only rarely carried out in industry today
since polyester production based on DMT shrunk tremendously and with this DMT
producers disappeared step by step during the last decade.
4.1 Background Information:
Plastics have had an impact on our culture. However, it has become obvious that there is
a price to be paid for their use. A controversy arose in the late 1950s and early 1960s
where there were a number of incidents where small children crawled into plastic bags
used by launderers to cover clothing, and suffocated to death. Plastics industry fended
off the trouble by launching a massive public-education campaign. Most local authorities
now offer collection facilities for plastic bottles either from your kerbside collection
scheme or at recycling centres. By late 1960s plastics were seen as the symbol for
backwardness. However, this was just a fashion statement, since plastics remained in
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widespread use anyway, and in many cases were much more effective and
environmentally benign than alternative materials. It also came with problems of litter
and waste disposal. The invention is however credited to Nathaniel Wyeth of Du Pont
according to the American Patent No. 3733309 of 1973.
Plastic was generally good, as it was durable and degraded very slowly. Burning of the
plastic material could release toxic fumes. The manufacture of plastics has generally
managed to create massive quantities of nasty chemical pollutants, and depleted the
Earth's bounded supply of fossil fuels. By the 1990s, Plastic recycling programs became
common in the 1990s (Lundquist, 2000). Thermoset plastics can be ground and used as
filler, thermoplastics can be re-melted and reused, though the purity of the material tends
to degrade with each reuse cycle. Automobile machines are now being redesigned to
make recycling of their large plastic parts much easier and cheaper. The Plastic Bottle
Institute of the Society of the Plastics Industry devised the now-familiar scheme to mark
plastic bottles by plastic type in order to assist in the recycling of plastic disposable
items. A container using this scheme is marked with a triangle with three "chasing
arrows" inside of it, which enclose a number giving the plastic type: PET, HDPE, PVC,
LDPE, PP, PS, and OTHER as shown in the table below.
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Plastic container code system:
MATERIAL PERCENT OF TOTAL
Polyethylene Terephthalate (PET) 20-30 percent
High Density Polyethylene 50-60 percent
Vinyl/Polyvinyl Chloride (PVC) 5-10 percent
Low Density Polyethylene 5-10 percent
Polypropylene 5-10 percent
Polystyrene 5-10 percent
All other resins 5-10 percent
4.1.2 Research questions and Hypotheses:
The assumptions of the study and the research questions are as follows:
i. Are plastics generally a menace to the environment and society at large?
ii. Can plastics be eradicated completely from our environment?
iii. What are the major cost benefit analyses of the plastic materials?
iv. What are the benefits of using PET plastics?
v. Are there other materials that can replace in the PET plastics in the common
market?
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vi. Recycling of PET is much better than producing new plastics.
vii. Recycling of PET reduces environmental pollution.
viii. Recycled PET is the material of choice to be used.
ix. Recycling PET comes with its’ demerits.
x. Recycling of PET reduces costs and is much cheaper than the virgin type.
4.2 Methodology:
Recycling plastics has proved to be very difficult. It is difficult to Automating the sorting
of plastic waste is very difficult, and so it is labor-intensive (Harper, 2000). Consumer
toy like a cellular phone may be made of many small parts consisting of over a dozen
different types and colors of plastics yet containers are usually made from a single type
and color of plastic, making them relatively easy to sort out. As the value of the material
is low, Recycling plastics is unprofitable and for this reason, the percentage of plastics
recycled is very small, that is around 5%.
Research is being conducted on "biodegradable" plastics that break down with exposure
to sunlight. By mixing starch with plastic degradation will be lowered, but it still doesn't
lead to complete breakdown of the plastic. Bacteria have been genetically engineered that
synthesize a completely biodegradable plastic, but this material is expensive at present.
Critics claim that their only real problem to be addressed is roadside litter, which is
regarded as a secondary issue. When plastics are dumped into landfills, they can become
"mummified" and persist for decades even if they are supposed to be biodegradable.
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The Courtald, the original producer of rayon, came up with a revised process for the
material in the mid-1980s to produce tencel which has superior properties to rayon, but is
still produced from "biomass" feedstock, and its manufacture is extraordinarily clean by
the standards of plastic production. I believe that effective and consistent education
encourages consumers to recycle. When both adults and children understand how
recycled containers are re-processed and re-manufactured into new items, it helps them
understand and take ownership of the process.
For a successful recycling operation to be achieved, the following requirements must be
put into place. First of all acquire a very steady source of very high grade and competitive
materials. After which, establish a cost effective transportation and collection medium.
Create a recycling processing technology and indeed equipment that can handle the
material efficiently and economically. Ensure you develop the ability to market both
continuous and quality in the quantity of materials. Finally develop proper markets for
end products.
5.1 Results:
Not all plastics that go into the curbside recycling bin get recycled. Collecting plastics
brings the belief that, like aluminum and glass, the recovered material is converted into
new containers. None of the recovered plastic containers from Berkeley are being made
into containers again, but into new secondary products such as textiles, parking lot
bumpers, or plastic lumber which are all non recyclable products. "Recycled" just means
"collected," not reprocessed or converted into useful products.
20
Curbside collection does not reduce the amount of plastic landfilled. This is because
people feel comfortable buying more when collection seems to be environmental
friendly. The programs might backfire if total use rises faster than collection The curbside
program only captures certain types of plastics thus most will end up in the landfills and
therefore the net impact of initiating curbside collection could be an increase in the
amount of plastic landfilled. According to Berkeley, no reduction of plastic being sent to
the landfill in the areas where the curbside collection was in operation was recorded.
Most plastic reprocessing leads to secondary products that are not themselves recycled
and thus temporarily diverted from landfills.
The chasing arrows symbols are misleading and are now considered meaningless. All are
marked with the chasing arrows symbol.Information in the symbol gives the general class
of resin used to make the container. Eleven attorneys general from different states
objected to false and misleading claims about plastic recyclability. The settlement that
they reached paves the way for a first-ever definition of what claims can or cannot be
made about plastic recycling and recyclability (Harper, 2000).
Plastic resins are not made from petroleum refineries’ waste, but from non-renewable
natural resources that could be used for a variety of other applications or conserved. It
could sound absurd, but plastics are made from the same natural gas used in homes to
heat water and cook. Plastic recyclers do not pay for the service. The advertisements are
paid for by the virgin resin producers. Their goal is to promote plastic sales. Their major
aim is to remove or otherwise diminish the greatest challenge to the market expansion
brought about by the virgin plastics. They also aim at elleviating the negative public
21
conception of plastic as unrecyclable, environmentally harmful, and a major component
of wastes that must be landfilled or burned.
Using plastics will not conserve energy. Manufacture of new plastic uses as much energy
as making glass containers from virgin materials. It also uses more energy than in the one
used in making glass containers from recycled materials. Refillables are the most energy
conservatives.
There are other choices to be adopted which include using refillable containers, buying in
bulk, buying things that don’t need much packaging, and buying things in recyclable and
recycled packages.
There are economic, health, and environmental costs and benefits of plastics. It is flexible
and light weight, but on the other hand creates problems including: consumption of fossil
resources; pollution; high energy use in manufacturing; accumulation of wasted plastic in
the environment; and migration of polymers and additives into foods (Eiri, 2007). The
producers do not use any recycled plastic in their packaging. Enactment of laws could
reduce the use of virgin resin for packaging. The virgin & endash plastics industry has
resisted such cooperation by strongly opposing recycled content legislation. It has instead
defeated or weakened consumer efforts to institute stronger laws. Plastic producers
decided that they will not add post consumer materials to their resins.
Establishing plastics collection might increase consumption by making plastic appear
more ecologically friendly both to consumers and retailers. Curbside collection could
legitimize the production and marketing of packaging made from virgin plastic. showed
No reduction of "recyclable" plastic containers being thrown away according to studies of
22
garbage truck loads during the recent plastic pick-up pilot program (Harper, 2002).
Indeed there was a slight increase. Due in part to increased plastic use, Glass container
plants have been closing, including Anchor Glass Container Corporation in Antioch,
putting 300 people out of work.
Plastic recycling is costly and does little to achieve recycling goals. The cost benefit
analysis for implementing curbside plastics collection in Berkeley shows that curbside
collection of discarded plastics has several pitfalls. It involves expensive processing; has
limited benefits in reducing environmental impacts; and has limited benefits in diverting
resources from waste. Processing plastics costs more than virgin plastic. As they increase
production and reduce prices on virgin plastics, the markets for used plastic are
diminishing. Competition is too high for the PET recyclers. The capture of glass, paper or
yard debris in Berkeley could divert more resources from landfills than collecting plastics
at curbside.
However, there are some benefits associated with the recycling of plastics. It reduces the
trash deposited in landfills, and offers the opportunity for consumers to clean and reuse
containers for everything from water spritzer bottles to holding excess amounts of
shampoos, cleaning fluids or lotions. Recycling all plastic bottles that contain PET or
HDPE labels somewhere on the bottle, most often found on the neck of the bottle to make
separation of recyclable and non-recyclable plastic easier on consumers is a better
remedy.
23
The PET bottle or jar that you place in a recycling bin today can be collected and
recycled into a wealth of products for tomorrow. PET can be recycled into new PET
containers, carpet, clothing, protective packaging, industrial strapping, automotive parts,
construction materials, even the felt for tennis balls, and tennis ball canisters (Gehrke,
2010). Because of PET's full recyclability and wide variety of uses, the market for
recycled PET is limited only by the amount of material that is collected from consumers
and recycling facilities. The development of new facilities that can recycle used PET
bottles into new food-grade PET bottles and containers (closed-loop recycling) is
expanding the resource efficiencies and sustainability of PET even further.
Cost Benefit Analysis of the Different plastics:
Net benefits ($/tonne) of recycling PET:
.
Text description of figure
24
Dotted line = no externalities included; solid lines: high and low benefit estimates.
There are indeed encouraging and appealing net benefits for recycling PET for all
quantities that are recoverable. It further shows that the net benefit curves are generally
flat. They are decreasing relatively with increased quantities
Net benefits ($/tonne) of recycling HDPE:
Text description of figure:
This line graph shows the net benefits ($/tonne) of recycling HDPE. There are positive
net benefits for recycling HDPE for all quantities that are recoverable. It shows that the
net benefit curves are generally flat and thus is decreasing relatively with increased
quantities.
25
Net benefits ($/tonne) of recycling PVC:
Text description of figure:
This line graph shows the net benefits ($/tonne) of recycling PVC. Only the curve
representing the high benefit estimate shows positive net benefits. Both the curves
representing low benefit estimates and that with no externalities included show negative
net benefits. All curves are fairly flat, the net benefit decreasing (or negative net benefit
increasing) slightly with increased quantities.
26
Net benefits ($/tonne) of recycling LDPE:
Text description of figure:
This line graph shows the net benefits ($/tonne) of recycling LDPE. As with Figure 15,
only the curve representing the high benefit estimate shows positive net benefits. Both the
curves representing low benefit estimates and those with no externalities included show
negative net benefits. All curves are fairly flat, the net benefit decreasing (or negative net
benefit increasing) slightly with increased quantities.
From the four figures above we can deduce that there are positive net benefits for
recycling PET and HDPE for all quantities that are recoverable. On the other hand for
PVC and LDPE, the value of recycling depends crucially on the estimates made of the
value of external benefits and particularly the direct consumer benefits. It gives the total
quantity produced. This is through the use of current technologies. It further gives the
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quantities that could be recycled for each material with positive net benefits under high
and low benefit assumptions.
There are a number of strategies that can be used to curb the problems or menace above.
First is the reduction in the usage. Retailers and consumers can select products that use
little or no packaging. Choose packaging materials that are recycled into new packaging
such as glass and paper (Carl, 2005). Should individuals refuse plastic as a packaging
material, the industry will decrease production for that purpose, and the associated
problems such as energy use, pollution, and adverse health effects will diminish.
The other strategy is to foster and encourage the culture of re-using containers.
Containers can be reused about 25 times, container reuse can lead to a substantial
reduction in the demand for disposable plastic, and reduced use of materials and energy,
with the consequent reduced environmental impacts. Container designers will have to
consider the difference in the following policies "Design for service” and "design for
disposal". This will enable them to take into account the fate of the container beyond the
point of sale and consider the service the container provides.
The producers also need to take back resins as a major requirement. If manufacturers
directly involved with plastic disposal and closing the material loop, then this would
stimulate them to consider the product’s life cycle from cradle to grave. Reprocessing
should be made easier by limiting the number of container types and shapes, using only
one type of resin in each container, making collapsible containers, eliminating pigments,
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using water-dispersible adhesives for labels, and phasing out associated metals such as
aluminum seals. They can help develop the reprocessing infrastructure by taking back
plastic from consumers.
A legislature requiring that all containers be composed of a specific percentage of post-
consumer material will reduce the amount of virgin material consumed. There should be
a standardized form of labeling (Gleick, 2010). The chasing arrows should not mislead
the consumers unnecessarily. Different standardized labels for recycled, recyclable and
plastic type X should be developed. On the contrary, recycling saves money in disposal
costs, extends disposal capacity, conserves natural resources, creates jobs, and provides a
reliable, cost-effective feed stock to industry.
Plastic is one of humanity's greatest sins against the environment, a wrong for which only
recycling can salvage. Recycling of plastics comes with its’ negative impacts too. It
cannot be read as with simplicity, but elements like to save the planet, reducing
greenhouse gases and saving marine life must be given priority. The change brought
about in the environment by recycling plastics depends on what type of plastic is
collected, destination and the final product. Recycling helps reduce the amount of trash
going into landfills across the country and offers the opportunity to reprocess and re-use
items to create objects, fabrics and items that we never would have imagined.
Recycled plastics are used to create carpet fibers, clothing and dishes, among others.
When plastics are recycled or burned, they release toxic waste or fumes from chemicals
inside the plastic out into the environment. This is aggravated by the fact that some
recycling facilities don't take green plastic bottles, such as those used to create soft drinks
29
like Mountain Dew or 7-Up. Recycling takes much time. Sorting and separation of daily
household or office trash takes time to separate papers from magazines, and clear plastic
from colored plastics. The numerous and variable usage of the plastic bottles brings a lot
of confusion. They hold everything from soda to ketchup and peanut butter or shampoos,
each which may require different handling or sorting instructions.
6.1 Discussion:
Consumers and businesses must participate actively in the recycling process in order to
gain most of the PET’s environmental sustainability and benefits. Though PET is the
most recycled plastic in the world at a rate of approximately 28%, there is still need to
improve in this sector accordingly to meet the demands of the people. It is however very
unfortunate that some individuals still carelessly toss their used bottles right into the trash
bin rather than putting them into the recycle bin (Board, 2007). These therefore end up in
landfills instead of being recycled for new uses. Due to its’ being inert and resistant to
micro-organisms, PET materials that go into the landfills will pose no risk of leaching or
contamination of groundwater. They at the same time take very little space since they are
easy to crush. About 1% of municipal solid waste is attributed to the PET.
PET containers can be collected or in other words recovered and re-used over again and
again. Reduction of waste, re-use of materials and recycling are the best processes so far
that can save the environment and the society at large. In order to attain a much more
sustainable future, it is indeed necessary to recycle PET bottles and containers. This is
because the process is simple and environment friendly. The production of new plastic
materials from already recycled materials indeed uses about 67% less energy than in the
30
manufacture of the products from virgin materials. This therefore implies that recycling
of plastics frees the energy that could be utilized somewhere else. For example in the year
2008 UK recycled over 5 billion pounds of plastic and this amazingly saved the energy
that could be used to heat over 2.5 million homes.
Greenhouse gas emissions arising from the extraction, pre processing and production are
significantly reduced with the substitution of recycled materials with the virgin materials.
Generally the recycled materials give an environmentally friendly source of producing
new products and substitutes for new plastics. The recycled materials make thousands of
everyday products. These include: fleece jackets, carpeting and lumber for outdoor
decking. The more plastics are recycled, the more of recycled plastics available.
Furthermore, the more plastics are bought then the more the industry shall create. Given
the current green trends, the demand for plastics may grow very exponentially. This is
given by the fact that the demand for plastic materials exceeds the industry’s supply. This
therefore calls for an elaborate recycling process to help meet the demands of the people.
Due to these factors the number of plastics recycling plants has tripled in the recent years.
Just imagine that the recycling of one tone of plastic saves about 7.4 cubic yards of
landfill space. Reduction is therefore an important achievement in the recycling industry.
New developments are also being carried out to ensure quality plastics are produced. For
example some bottled water producers are trying to reduce plastic in their production
which is otherwise known as light weighting in order to create an impact. The recycling
industry in response to this managed to reduce the weight of PET plastic water bottles by
nearly 33% between the year 2000 and 2008. Currently the average weight of 2 litre
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bottle of soda is about 19 grams lighter than it was in 1977. An approximate of 5.6 billion
bottles are sold every year therefore the simple source reduction has managed to
eliminate about 200 million pounds of plastic every year.
On the other perspective, recycling of plastics could help in eliminating the negative
impacts associated with plastics. Studies have suggested that most of the world’s fossil
fuels are used in producing new plastics. This accounts for millions of tons of fuels per
year in the environment. Therefore, recycling helps in the preservation of these fuels. It
goes ahead to encourage their use in other markets. Since all plastics recyclable, it should
be recycled as much as possible. This is on the contrary not being done so and thus leads
to massive accumulation of plastics in the landfills. It therefore clearly points out that
without proper recycling then the marine life is in complete danger.
The landfills are closing at an alarming. Two are being closed daily. This space crisis is
especially problematic in cities, where inner-city trash dumps are often filled to capacity,
and surrounding communities are unwilling to allow new landfills to come to their
neighbourhoods. Cities along the coast line use the ocean as a dumping ground, resulting
in depleted fish stock, polluted beaches, and other health issues for the inhabitants. Plastic
materials make up about 11% of the contents of landfills. So without this recycling
project then there is will no land in future for other developments. In order to save space
at landfills, plastics are often burned using incinerators. By doing this, chemicals,
petroleum, and fossil fuels used in the manufacturing process are released into the
atmosphere, adding to greenhouse gas emissions. Recycling would eliminate this by a
great margin.
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Most plastic containers float on the surface of the oceans. These at times can look like
food to larger sea animal, but it comes with fatal consequences. Sea birds, fish and other
ocean creatures often get caught in plastic rings that strangle them or constrict their
throats so that they cannot swallow. Imagine how recycling could save much life not only
to humans, but to animals also. Research is not quite clear on how long it takes for plastic
to biodegrade. Though it has not been round long enough, but amazingly the first plastics
made are still around today. However, plastics will take hundreds of years to degrade
fully or even much longer. Plastics have only been around for a hundred years, yet they
are already a problem. What amount of plastics will be in our landfills in about five
hundred years to come.
Plastics generally contain harmful chemicals which include, but not limited to the
following: cadmium, lead, PVC, and other pollutants in the form of artificial coloring,
plasticizers, and stabilizers (Bary, 2003). Some have been found to be harmful and are
not in currently manufactured plastics, but the older, more toxic plastics are still filling up
our landfills and floating around in our oceans, releasing pollutants into the environment.
They may find their way into groundwater from landfill runoff and cause health risks for
both wildlife and humans. Energy saved by recycling a single plastic bottle as compared
to producing a new one from scratch is enough to power a single 60-watt bulb for six
hours. This would power our homes on the energy savings we would gain by recycling
every one of those plastic bottles. It is a general fact that recycled plastic materials are
found in many unexpected places. These may include: carpeting, the fuzz on tennis balls,
scouring pads, paintbrushes, clothes, industrial strapping, shower stalls, drainpipes,
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flowerpots, and lumber. Plastics may also contain oils that could be recycled and reused
as fossil fuels.
The recycling process also came up with its hindrances or difficulties. The first problem
is the issue of contamination. According to nature of impurities, basic washing can solve
this menace. There is also insufficient supply of the plastics for recycling. Some plastics
are also too thin to recycle. Plastics have different molecular construction, practical
recycling will depend majorly on the ability to separate them from each other. This
therefore calls for recycling with proper sorting and packaging. Some consumers view
plastics as low quality associated with the low class individuals.
Some legislations also prevent the use of plastics. This is detrimental to the market
potential of the plastic products. Polymer prices are also very volatile due to the
inequality in capacity demand, stock building during the low price situations. The price
of virgin plastic is also linked to the oil price. The high collection costs hinder the general
process of recycling. Proper development of sorting machines will reduce collecting and
sorting costs and at the same time increasing the plastic streams quality.
7.1 Conclusion:
To crown up issues concerning PET Plastics and PET recycling, it is of importance to
note that this project is of indeed good value. PET containers can be collected or in other
words recovered and re-used over again and again. Reduction of waste, re-use of
materials and recycling are the best processes so far that can save the environment and
the society at large. In order to attain a much more sustainable future, it is indeed
34
necessary to recycle PET bottles and containers. This is because the process is simple and
environment friendly.
Research is not quite clear on how long it takes for plastic to biodegrade. Though it has
not been round long enough, but amazingly the first plastics made are still around today.
However, plastics will take hundreds of years to degrade fully or even much longer.
Plastics have only been around for a hundred years, yet they are already a problem. What
amount of plastics will be in our landfills in about five hundred years to come.
The production of new plastic materials from already recycled materials indeed uses
about 67% less energy than in the manufacture of the products from virgin materials.
This therefore implies that recycling of plastics frees the energy that could be utilized
somewhere else. For example in the year 2008 UK recycled over 5 billion pounds of
plastic and this amazingly saved the energy that could be used to heat over 2.5 million
homes.
Recycling of plastics could help in eliminating the negative impacts associated with
plastics. Studies have suggested that most of the world’s fossil fuels are used in
producing new plastics (Baird, 2004). This accounts for millions of tons of fuels per year
in the environment. Therefore, recycling helps in the preservation of these fuels. It goes
ahead to encourage their use in other markets. Since all plastics recyclable, it should be
recycled as much as possible. This is on the contrary not being done so and thus leads to
massive accumulation of plastics in the landfills. It therefore clearly points out that
without proper recycling then the marine life is in complete danger.
35
According to nature of impurities, basic washing can solve this menace. There is also
insufficient supply of the plastics for recycling. Some plastics are also too thin to recycle.
Plastics have different molecular construction, practical recycling will depend majorly on
the ability to separate them from each other. This therefore calls for recycling with proper
sorting and packaging. Some consumers view plastics as low quality associated with the
low class individuals.
8.1 Recommendations:
In the early 70’s not even a single curbside was found in any of the countries. Currently
they have grown to unimaginable numbers. Most countries manage to recycle third their
municipal waste. The rate of dumping still exceeds that of recycling. Increasing our
recycling rates will help pull us out of the garbage heap and reduce global warming
emissions. This brings us down to the realization that it is necessary to cut down on the
waste we produce in the first place. Recycling is one of the steps in a full loop of
practices that, together, will reduce the amount of waste going to landfills and cut back
on greenhouse gas emissions. It goes beyond bundling up newspapers and collecting
bottles. Manufacturers should use recycled materials to make their products, and
consumers should buy goods made from post-consumer recycled content in order to close
the loop created. Demand for products made with recycled materials should be increased
at the expense of virgin materials. This will eventually ensure a much more successful
recycling, divert waste from landfills, save natural resources and curb global warming.
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Other avenues to work towards a zero waste in the future are as follows: Organics and
recyclables should be kept out of landfills and incinerators. Approximately 60 percent of
household waste is recyclable or compostable, but only 8% are being composted.
Composting helps in preparing organic waste like leftover food and lawn trimmings for
reuse as fertilizer instead of leaving it to decompose in landfills or to combust in
incinerators, which emit greenhouse gases and other air pollutants. Creating More
municipal composting programs should be created to boost composting rates. The
programs exist in only a few cities, and they're outnumbered more than 2 to 1 by curbside
recycling programs.
We should also consider putting trash cans in our regular diets. What we dump in our
trash cans doesn't need to be there in whole. By adopting mechanisms of cutting back on
product packaging, promoting reusable bags over paper and plastic, using sponges
instead of paper towels, and favoring mugs or glasses over disposable containers, we are
indeed just reducing the waste.
There are also ways to boost the rates of recycling and also to curb the menace of global
warming. Throwing away our waste creates greenhouse gas emissions just exactly like
from driving our cars and heating our homes. Depositing garbage in landfills releases one
fourth of all methane gas emissions (Andrady, 2003). Contrary to most opinions, methane
gas is a global warming pollutant which is 22 times more potent than carbon dioxide.
Trash incinerators emit greenhouse gases. Therefore throwing away products rather than
reusing or recycling them often means burning more fossil fuels to strip virgin timber and
other raw materials from the earth. If we increase our recycling rate from the current 32.5
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percent to 35 percent, the effect on greenhouse gas emissions would be comparable to
removing a million passenger cars from our roads.
Managing the electronic waste is a major concern in the future. Used and dumped
electronics like old computers, broken cell phones, obsolete television sets will form the
fastest growing element of our waste stream. Laws are in place for nine states that require
the recycling of electronics, and several other states are working on new e-waste laws in
America. Most countries support legislations that put the responsibility on manufacturers
to recycle their used products, and for designing less toxic, more recyclable gadgets in the
first place.
The current bottle bills should also be expanded even to other countries. In 2005, 2
million tons of plastic bottles in the United States ended up in the trash instead of in
recycling bins. The State container deposit law which is known as "bottle bills" are long
overdue for an upgrade. They have proven to be the most effective approach to collecting
bottles and cans. Currently, only 11 states have bottle bills in America, and most of them
include only beer and soda bottles but not water bottles, which accounted for 14 percent
of bottled beverages in 2005. Such bill with a higher deposit would give a huge boost to
our bottle recycling rates.
Plastic bags should also be ditched and left completely. EPA has recorded that the United
States consumes about 380 billion plastic bags a year and recycles less than 5 percent of
them. Reusing shopping bags just as is common in some other countries could reduce that
number significantly and prevent billions of plastic bags from ending up in landfills
(Auckman, 2007). It could also prevent them from getting into the ocean, on trees and
38
floating by your window. It is necessary to address the plastic problem. San Francisco
banned the use and distribution of plastic bags by grocery stores in 2007. Other stores
around the country are creating incentives for shoppers to reduce plastic bag use, such as
offering cash back for reused bags, selling branded reusable bags and installing in-store
bag drop-off stations to encourage reuse. This is a good strategy for future advancement
in this sector.
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9.1 References:
Ackerman, Frank. (2007). Why Do We Recycle? Markets, Values, and Public Policy.
Iland Press.
Andrady A. L. (2003). Plastics and Environment. New York: Wiley-IEEE.
Baird, Colin (2004) Environmental Chemistry (3rd ed.). New York, W. H. Freeman.
Bary E. A. (2003). Handbook of Plastic Films. London: iSmithers rapra Publishing.
Board E. E. (2007). Plastic Compounding, Masterbatches, PET and Other Plastic
Processing Industries. New Delhi: Engineers India Research In.
Carl A. Zimring (2005). Cash for Your Trash: Scrap Recycling in America. New Jersey:
Rutgers University Press.
Eiri (2007). Handbook of Polymer & Plastic Technology. New Delhi: Engineers India
Research In.
Gehrke R. (2010). Recycling Projects for the Evil Genius. New York: McGraw-Hill
Professional.
Gleick P. H. (2010). Bottled and Sold: The Story Behind our Obsession with Bottled
Water. London: Island Press.
Harper C. A. (2006). Handbook of Plastics Technologies: The Complete Guide to
Properties and Performance. New York: McGraw-Hill Professional.
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Harper C. A. (2002). Handbook of Plastics, Elastomers and Composites. New York:
McGraw-Hill Professional.
Harper C. A. (2000). Modern Plastics Handbook. New York: McGraw-Hill Professional.
Hulse S. (2000). Plastics Product Recycling: A Rapra Industry Analysis Report. London:
iSmithers Rapra Publishing.
Lundquist L. (2000). Life Cycle Engineering of Plastics: Technology, Economy, and the
Environment. New Jersey: Elsevier.
Mantia F. L. (2002). Handbook of Plastics Recycling. London: iSmithers Rapra
Publishing.
Piringer O. G. (2000). Plastic Packaging Materials for Food: Barrier Function, Mass
Transport. Quality Assurance and Legislation. New York: John Wiley and Sons
Porter, Richard. (2002). The economics of waste. Resources for the Future.
Thomas S. & Visakh P. M. (2011). Handbook of Engineering and Speciality
Thermoplastics. New York: John Wiley and Sons.
Tierney, John. (2006). Recycling Is Garbage. The New York Times.
Tukker A. (2002). Plastics Waste: Feedstock Recycling, Chemical Recycling and
incineration. London: Smithers Rapra Publishing.
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