This report aims to request for funds to aid
on the research on recycling Polyethylene Terephthalate (PET) bottles for
construction materials. According to National Environment Agency, it was
estimated that 1.76 billion plastic items were used a year in Singapore, and
only 6% of the waste plastics were being recycled (NEA, 2017). Out of the 1.76
billion plastic wastes, 467 million are PET bottles. The reason why plastic was
used at an abundance is due to its ability to form into different forms and for
its durability, but the disadvantage is that plastic items would take centuries
to be decomposed naturally and landfills. The plastic that were not recycled
would be incinerated and be shipped to Pulau Semakau Landfill (NEA, n.d.). It
was originally estimated that Pulau Semakau Landfill would be able to sustain
until 2045, but due to the increasing reliance on disposable plastic products,
the current estimation is that the landfill would run out of space by 2035
(MEWR, n.d.).
Currently, the two main ways Singapore
disposes of waste plastic is by burning it and disposing it to the landfills or
sell the waste to other countries that are willing to buy it (Aqil, 2018). The
same author also mentioned that the practice of burning waste plastic would cut
down the amount of space needed in the landfills, but it is very harmful to our
environment.
According to Aqil (2018), It was reported that
the fumes produce from burning plastic posed harmful health risk such as,
increase the risk of heart disease, aggravate asthma and cause damage to the
human nervous system. Aqil (2018) also mentioned that Singapore sold
approximately 42,000 tons of waste plastic to China, Malaysia, Vietnam and
Indonesia in 2016. With China’s recent announcement of banning imported
“foreign garbage”, it would post a major problem as Singapore’s biggest plastic
waste buyer is China (Aqil, 2018).
With the plastic waste management challenges
Singapore is facing, creative ideas for plastic recycling should be implemented
to reduce the harmful impacts. According to BCA, Singapore is expecting to have
a higher volume of construction activities per annum, as Singapore is still
developing (BCA, n.d.).
The main stakeholders for the application of
recycled would be the Building and Construction Authority (BCA), as BCA
governing the quality control of all construction materials and methods.
Singapore has been using natural resources of fine and coarse aggregates in the
mixture of concrete. In a BCA handout, it was stated that ECO-Concrete which
are concrete that consisted of 50% or more recycled content (BCA, n.d.).
BCA had set rules and standards for the
quality of building materials to be used in Singapore for contractors to
strictly adhere to. With the given BCA standards, lab test and research can be
done to the recycled polyethylene to be introduced into the concrete as a
replacement of natural aggregates (BCA, n.d.).
With the lack of space in Semakau Landfill,
the production of air pollution through the incineration of plastics and the
significantly low recycling rate, Singapore have to find an alternative
solution for disposing of plastic waste. Singapore authorities should start
adopting the use of recycling plastics into green aggregates and find
alternative ways to incorporate the waste plastic to other forms of
construction materials to ultimately reduce the contribution of plastic waste
to our landfill.
Currently, the percentage of plastic waste not
being recycled is at 94%. With the aim of being a “zero waste” nation, the ideal
goal is for Singapore to no longer rely on landfill as a means to dispose of
our plastic waste, but through alternative methods. One solution is to utilise
the waste plastic by converting them into green construction material. With
this, not only are we working towards a “zero-waste” nation but also extending
the life spend of landfills for other waste disposals.
The purpose of this report is to propose the
adoption of green aggregates by recycling waste PET bottles. The aim is to increase
the percentage of recycling rate of waste plastic, reducing the usage of space
in Pulau Semakau Landfill and lessen the production of air pollution through
the burning of plastic waste. Adopting this solution would bring Singapore a
step closer to being a “zero waste” nation.
BCA developed an initiative by encouraging the
use of recycled concrete materials by incorporating Recycled Concrete Aggregate
(RCA) into the production of concrete. RCA are aggregates that are recovered
from the demolition of buildings, where demolition debris are then crushed and
sieved into different category of aggregates. (BCA, n.d.)
Sands and granites are deemed as aggregates in
the concrete mixture, and the roles of aggregates in a concrete mixture are to
give the basic property which determines the concrete behaviour such as
durability, strength and workability. The quality of concrete depends heavily
on the aggregates properties, which would determine the ultimate property of
the concrete produced. As natural resources are of a scar in Singapore,
construction companies have to rely on other countries as these natural
resources are imported into Singapore. (BCA, n.d.)
According to Thorneycroft et al. (2018), India
had been researching on the possible ways to recycle plastic into construction
base material in recent years. The research had shown that PET bottles could be
ground and blended to achieve sand like textural which allows it to replace
natural sand and act as a fine aggregate in the concrete mixture. The same
author also mentioned that due to PET having a different chemical property as
natural sands, it bonds differently with cement matrix causing the concrete to
have a weaker strength and durability. However, by treating PET with chemicals
and reducing the size of the PET particles, the reaction bond between the PET
and cement matrix is showing improvement (Thorneycroft et al. 2018).
Brick is a type of building material that used
to make walls, pavements and other elements in masonry construction. Bricks are
typically made up of shaped clay and are bind together with the usage of cement
mortar during construction (Juan, 2018).
Zhuang (2014) stated that during 1990s, houses
in Singapore were built out of bricks. The same author mentioned that as
technology advanced, Singapore had become “a city of glass and steel
skyscrapers” (Zhuang, 2014, para 1). Zhuang (2014) also mentioned that
Singapore no longer has any brick factories, hence all brick used in Singapore
were imported from overseas. Bricks are no longer visible is because
contractors tend to paint over facing bricks or plastering it up so only the
plaster work can be seen and not the bricks (Zhuang, 2014).
According to Fedreico et al. (2017), the
properties of an eco-bricks highly depends on the compactions of the filling
materials into the bottles, and skilled workers are required to compact the
fillers into the bottles to have a desirable brick property. The same author
also mentioned that Eco-bricks are required to undergo the flammability test
before using the eco-bricks for actual construction works.
Himanshu (2017) mentioned that PET bottles are
able to be transformed into construction bricks, by compacting sand into the
plastic bottles and giving it the ideal strength which is comparable to
original bricks. The same author also stated that by sorting the PET bottles
into different size and shape, and a strict selection of suitable PET bottles,
the bottles are then compacted and filled with sand, this sand filled bottles
are then deemed as ECO-bricks. This ECO-bricks would be stacked and cemented
together, creating a partition walls that is made up of plastic bottles and
cement mortar (Himanshu, 2017).
The potential benefits of the proposed solution
include, conserving natural resources, relieving stress on landfill and
improved properties to concrete.
According to the Portland Cement Association
(n.d.), approximately 60%-75% of the concrete is made up of aggregates, on
average 1370 tonnes of aggregates are used a year in Singapore. That
contributes to a hefty amount of percentage in the mixture of cement.
In the 4th quarter of 2018, Singapore’s
construction industry average usage of cement was estimated to be 377 000
tonnes. Adopting waste plastic aggregates would help conserve natural resources
by reducing the need for virgin materials (BCA, 2019).
Figure 1: Forecast and actual construction demand
(BCA, 2019)
The proposal of the creation and adopting of
plastic waste aggregates would redirect substantial amount of plastic waste away
from landfills, prolonging the lifespan of Pulau Semakau. It could potentially
reduce energy consumption and emissions from burning the waste.
Incorporating plastic aggregates improves
properties of concrete due to its toughness, low thermal conductivity, high
heat capacity and good abrasion behavior. Moreover, the incorporation lowers
the densities of the resulting concrete thus developing a ‘lightweight
concrete’. This development lowers the earthquake risk of a building and it
could be beneficial in the design of an earthquake-resistant building in the
future (Semiha, Cengiz, Kubiley, 2010, as cited in Saikia, Brito, 2013)
There are some challenges to overcome in order
to achieve our proposed solution. One challenge faced by the team is the cost
of sorting plastics. There is no exact cost stated in articles. According to
Quah (2018), V1 Recycle’s managing director Richard Lim stated that the sorting
process is the costly parts of the process as it requires expensive machines or
very skilled workers. On top of that contamination and land constraints affects
the cost of sorting plastics. Sorting of the plastics must be done in order to
remove contaminated plastics as it cannot be recycled. Skilled workers have to
be trained and educated to know and differentiate contaminated and
non-contaminated plastics apart.
Mr Dave Wong, a business development manager
at A~Star Plastic Recycling, mentioned that the cost of recycling plastics will
increase when plastic is contaminated as cleaning and sorting are required (Mahmud,
2018).
In order to raise awareness on the importance
of recycling, countries in Latin America such as Argentina, Africa and South
Asia have started adopting Eco-Bricks as part of a community project where
everyone works towards a common goal.
Ecoinclusion - a non-profit foundation, was
created in the hopes of solving environmental and infrastructure problems. With
the lack of decent housings, they decided to manufacture Eco-bricks where it
has the same properties as common ceramic bricks yet lighter and has a better
insulating and soundproofing properties. With this, they have the same
objectives as A-Green-Gates. They are reducing plastic pollution, increasing
awareness on the importance of recycling and help those sectors in need
(Ecoinclusion, 2018).
The team consulted with Dr Fei Jin, a
professor in civil engineering materials. He postulated that Singapore’s
construction companies have been sticking to traditional methods due to their
stubbornness and the cost of the construction. According to Ng (2017), property
consultant Nicholas Mak of SLP International mentioned that companies will
stick to traditional methods if it is cheaper. The purchase of machinery,
computer software and training of staffs will usually result in higher cost.
High-cost methods will result in local companies sticking to their traditional
method.
A survey questionnaire was posted online to a
total of 72 random Singaporeans as a form of a primary survey to determine if
Singaporeans have any prior knowledge on plastic waste management and to
showcase the importance of this proposal. Singaporeans are one of the main
stakeholders as they play a part in producing plastic waste. Furthermore, there
is a need to spread awareness of the importance of plastic waste.
This is crucial as the team wants to know if
the surveyees have similar views of plastic waste and the results of the survey
would help the team to convince the National Environment Agency (NEA) and
Building and Construction Authority (BCA) that Singaporeans are calling for
improvement in recycling efforts and that our proposed solution could be
potential way to recycle plastic.
The main source of secondary research is NEA
and BCA. An online journal published by Zainab Z. Ismail benefits the proposal
as a reliable source. This journal provides credible studies that prove that
“reusing waste plastic as a sand-substitution aggregate in concrete gives a
good approach to reduce the cost of the materials are problems posed by
plastics” (Zainab, 2008)
In conclusion, plastic
is the top contributor to the rapid influx of our landfills having the lowest
recycling percentage, with the adoption of converting waste plastic into
construction material would help increase Singapore’s plastic waste recycling
rate and reduce the amount of plastic from being burnt. The conversion will
then reduce the effect of plastic occupying the majority of the landfill space,
as plastic requires a long period of time to disintegrate.
By incorporating plastic
into construction materials, we are able to discover enhanced materials
properties for complex construction purposes. New and improved construction materials
with plastic incorporated could deliver a better result as compared to the
original materials, as plastic have a different physical property as compared
to traditional materials. This could help construction companies in Singapore
to explore more possible new construction methods with the new sustainable
products produced.
As the cost of sorting
plastics are very high, Singaporeans can play a huge part by sorting their
recyclables and disposing it into separate bins instead of the ‘blue recycling bins’
as a single-stream recycling. By having separate bins, the amount of effort and
time using to sort the waste rubbish would be saved.
We hope that BCA is able to provide adequate
aid in terms of research and development findings, which allows us to test and
identify any flaws to be rectified. This would allow us to adopt the usage of
the recycled plastic construction materials in the near future and allow us to
discover further benefits of this recycled plastic and put it into good use.
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