Recycling of plastic bottles

How many plastic bottles do you throw away per* No. 3 - Vinyl/Polyvinyl Chloride (PVC)
week? Soda, soft drinks and even water now comeFood wrap and water pipes are manufactured from
in plastic bottles. Nowadays, people tend to use morethese plastics.
plastic bottles than glass bottles, because they are* No. 4 - Low-density Polyethylene
lighter and easier to use and can be thrown awayMany plastic bags, shrink wrap and garment bags are
afterwards.made using these plastics.
Even though using plastics has its plus points, there are* No. 5 - Polypropene
major negative effects on the environment; plasticsRefrigerated containers, bottle tops and chairs are
contribute to environmental pollution on a major scale.manufactured from these plastics.
This may sound hard to believe, but around 1.5 million* No. 6 - Polystyrene
tons of plastic is used every year in the world just toThese plastics are used for meat packaging,
bottle water.throwaway packaging and protective packaging.
Let us tell you about plastics in detail. The word* No. 7 - Other usually layered or mixed plastics
‘plastics' is used to describe a wide variety ofThere is no PET recycling machine potential for these
resins or polymers with different characteristics.plastics. They must be discarded.
Do you know what polymers are? Polymers are aOut of these types, only PET recycling machine and
long chain of molecules, a group of many units, takingPE can be recycled. Though PET recycling machine is
its name from the Greek word ‘poly' (meaningnot done on a major scale in Sri Lanka, we have a
many) and ‘meros' (meaning parts or units).few small scale PET recycling plants here.
There are two types of plastics; thermoplastics andRecently, we visited one such PET bottle PET
thermoset plastics. Thermoplastic polymers can berecycling machine plant at Boralesgamuwa.
heated and formed repeatedly. The shape of this"We do not follow a complex recycling process here.
polymer molecule is linear (in a line) and slightlyWe turn these bottles into another ingredient and
branched.export it to China," said the owner of the recycling
This may give you the idea that the molecules canplant, Anura Jasenthuliyana.
flow under pressure when heated above their meltingAccording to Jasenthuliyana, they get around 20-30
point.tons of bottles per month through scavengers who
On the other hand, thermoset polymers undergo acollect these bottles from garbage dumps in the
chemical change when they are heated, creating aColombo City. When the bottles reach the PET
three-dimensional network. After they are heated andrecycling machine plant, they are sorted out.
formed once, these molecules cannot be reheated"We get only PET bottles, so, we don't have to worry
and reformed.about the type of plastic. We just sort the bottles
Plastic from a ‘blow-mould' (the neck of the bottleaccording to their colours", said Jasenthuliyana.
is narrower than the body) has a slightly different"The darker the bottle, the lower its selling price. When
structure from the plastic used in an ‘injectionreusing these bottles, manufacturers can use any
mould' (where the opening is the widest part of thecolour for the clear bottles, whereas for the shaded
product). Out of the two types of plastics,bottles, there's not much of an option; they can either
thermoplastics are easier to recycle.use the same colour or go for black," he explained.
Now that we have given an introduction about plastics,After the bottles are sorted out, they will be put into a
let's consider the PET recycling machine process; thismachine and crushed to small pieces.
differs according to the type of plastic we use. TheWe are exporting these pieces to China, where they
next problem is, how do we identify the type?will be melted and used to make polyester fabrics", he
Before answering that question, if you have a plasticsaid. Fabric made using these bottles is strong, warm
bottle closeby, turn it upside down and see whetherand durable.
there is a number placed inside a chasing arrow sign.The only problem with this fabric is that it doesn't have
Do you know what this number means?a glossy finish, instead it come with a matt finish. Five
Obviously, it's not just another useless mark on thePET recycling machine manufacturer bottles yield
bottle. This is known as the plastic identification or PETenough fibre for one extra large t-shirt, while 25
recycling machine manufacturer code. This codetwo-litre bottles can produce a sweater. PET is also
system was created by the Society for the plasticspun like cotton candy to make fibre filling for pillows
industry in the 1980s. Let us tell you what each numberand quilts. It can also be rolled into clear sheets or
means.ribbon to produce VCR and audio cassettes. Most
* No. 1 - Polyethylene Terephthalate (PET)products which are manufactured from recycled
These plastics are used to produce soda and watermaterial can't be recycled for the second time.
containers, some water-proof packaging and tennis"I operate this PET recycling machine plant as a social
balls.service, to help keep the city clean. I request the public
* No. 2 - High-density Polyethylene (PE)to help us in this course. What they can do is, sort out
These plastics are used to make milk, detergent and oilthe plastics in their households and hand them over to
bottles, toys and plastic bags.a plastic collection centre," said Jasenthuliyana.