ABSTRACT
Plastic was recognised as the most useful innovation in the 19th century by many scientists for
its unique characteristics. However, it has become the biggest environmental hazard in the 20th
century when it is disposed as waste. Plastic do not degrade naturally and when it is disposed in
an ad hoc manner, it creates numerous environmental problems that can deteriorate the life of
flora and fauna. Recycling is one of the most important actions currently available to reduce
these impacts and represents one of the most dynamic areas in the plastics industry today. The
principal aim of this study is to recycle plastic wastes with sawdust as an additive into a variety
of products like plastic tiles (ceiling tile), which are Civil Engineering materials. Mainly, sachet
water plastic wastes were collected for this experiment. The waste materials went through the
process of sorting, washing, cutting, drying and pre-melting before dividing into different
weight of 800grams, then recycling was done after heating to molten form and thoroughly
mixing with different particle sizes of sawdust as additive. Melting was done using locally
fabricated box furnace. The sawdust was sieved using sieves 6, 8, 10, 14 and 25 which
represented 6.25, 12.50, 18.75, 25.00 and 31.25% respectively of sawdust to 800grams of
plastic. After thoroughly mixing the sawdust with the molten plastic, it was then casted into the
mould and left to completely cool and in some cases left till the next day before removal from
the mould to form the plastic tile. Tensile and hardness tests were done on the materials; the
tensile strength test results varied as they showed higher tensile stress for some and low for
others. Hardness survey test was conducted at different points on each material and the results
showed that strength not uniformly distributed over all points of the tile and this result faulted
the recycling process. Engineering properties of the recycled materials were compared with
existing local and foreign tiles respectively and from the results, some of the produced
materials matched the qualities of the local tile and was even better than the foreign tiles.
Therefore, with improved recycling process plastic wastes can be converted into useful
products for the betterment of the environment.
TABLE OF CONTENTS
TITLE PAGE… … … … … … … … … … … i
CERTIFICATION PAGE… … … … … … … … … ii
DEDICATION… … … … … … … … … … … iii
ACKNOWLEDGEMENT… … … … … … … … … iv
ABSTRACT… … … … … … … … … … … v
TABLE OF CONTENTS… … … … … … … … … vi
LIST OF TABLES… … … … … … … … … … xi
LIST OF PLATES… … … … … … … … … … xii
LIST OF FIGURES… … … … … … … … … … xiii
ABBREVIATIONS… … … … … … … … … … xvi
CHAPTER ONE: INTRODUCTION
1.1 Background of study… … … … … … … … … … 1
1.2 Research problem… … … … … … … … … … 2
1.3 Research objectives… … … … … … … … … … 3
1.4 Significance of research… … … … … … … … … 4
1.5 Scope of Research… … … … … … … … … … 5
1.6 Research limitations… … … … … … … … … … 5
1.6.1 Collection was difficult and expensive… … … … … … … 6
1.6.2 Extensive sorting is required… … … … … … … … 6
1.6.3 Lack of recycling equipment… … … … … … … … 6
1.6.4 Inefficiency of the Recycling Process… … … … … … … 7
1.6.5 Greater Quantity of Waste Needed for Recycling… … … … … 7
CHAPTER TWO: LITERATURE REVIEW
2.1 Definition of Recycling… … … … … … … … … 8
2.2 History/Origin of Recycling…… … … … … … … … 8
vii
2.2.1 Recycling… … … … … … … … … … … 8
2.2.2 Overview of Plastics… … … … … … … … … 10
2.2.3 Overview of Plastic Recycling… … … … … … … … 14
2.2.3.1 Recycling codes… … … … … … … … … … 14
2.2.3.2 Plastic Recycling… … … … … … … … … … 14
2.2.3.3 Challenges in plastic Recycling… … … … … … … 15
2.2.3.4 Processes in plastic Recycling… … … … … … … … 15
2.3 Commonly Recycled Materials… … … … … … … … 16
2.4 Applications of Recycling in different kinds of plastics… … … … … 20
2.4.1 Polyethylene Terephthalate (PET or PETE)… … … … … … 22
2.4.2 Polyvinyl-Chloride (PVC)…… … … … … … … … 22
2.4.3 High Density polyethylene (HDPE)… … … … … … … 23
2.4.4 Polystyrene (PS)… … … … … … … … … … 23
2.4.5 Other Plastics… … … … … … … … … … 23
2.5 Plastics in the Society… … … … … … … … … 24
2.5.1 The Image of Plastics… … … … … … … … … 24
2.5.2 Production and Consumption of Plastics…… … … … … … 24
2.5.3 Plastics in Vehicles… … … … … … … … … 26
2.6 Ecological case for Recycling… … … … … … … … 29
2.6.1 Effects of the Environment on plastics… … … … … … … 31
viii
2.6.2 Environmental Aspects of Plastic Recycling… … … … … … 32
2.6.2.1 Raw Materials and Uses of Resource… … … … … … … 32
2.6.2.2 Plastic Products save Energy… … … … … … … … 32
2.6.2.3 Reduce, Reuse, Recycle and Recovery of Plastics… … … … … 33
2.6.2.4 Recycling and the Environment… … … … … … … 33
2.7 Environmental Impacts of Polyethene Plastic Generation and Disposal in Nigeria… 34
2.8 Systems for Plastic Recycling… … … … … … … … 37
2.9 Advantages and Disadvantage of Recycling… … … … … … 41
2.9.1 Advantages of Recycling… … … … … … … … … 42
2.9.2 Disadvantage of Recycling… … … … … … … … 43
2.10 Solid Waste Management Overview… … … … … … … 44
2.11 Public Support for Recycling… … … … … … … … 50
2.12 Economic Issues Relating to Recycling… … … … … … … 51
2.13 Current Trends in Plastic Recycling… … … … … … … 53
2.14 Challenges and Opportunities for Improving Plastic Recycling… … … 53
2.15 Actions to Boost Recycling of Plastics… … … … … … … 54
2.16 Wear characteristics of Plastics… … … … … … … … 63
2.17 Conditions for material selection of Plastics… … … … … … 63
2.18 Sawdust Overview… … … … … … … … … … 66
2.24 CHAPTER THREE: EXPERIMENTAL METHODS AND MATERIALS
ix
3.1 Experimental Apparatus… … … … … … … … … 69
3.1 Source of Samples… … … … … … … … … … 69
3.3 Rate of Generation of Waste Plastic Materials… … … … … … 70
3.4 Material Preparation… … … … … … … … … … 70
3.4.1 Sample Preparation for Plastic Materials… … … … … … 70
3.4.2 Sample Preparation for Sawdust… … … … … … … … 70
3.5 Fabrication of Crucible and Moulds… … … … … … … 71
3.6 Mode of Operation of the Box furnace… … … … … … … 71
3.7 Experimental Procedure… … … … … … … … … 74
3.8 Inefficiency of the Recycling Process… … … … … … … 75
3.9 Method of Laboratory test on Materials… … … … … … … 76
3.9.1 Tensile Strength Test… … … … … … … … … 76
3.9.2 Hardness Test… … … … … … … … … … 76
3.10 Recycling Process Involved in this Research… … … … … … 78
3.11 Other Equipment Required for Plastic Recycling Processes… … … … 79
3.12 Mechanical and Physical Properties of Plastics… … … … … … 85
CHAPTER FOUR: RESULTS AND DISCUSSIONS
4.1 Presentation of Results… … … … … … … … … 105
4.2 Effect of Particle size on Strength properties… … … … … … 105
4.3 Effect of Particle weight on strength properties… … … … … … 110
x
4.4 Variation of Strength properties within material… … … … … … 114
4.5 Comparative Analysis between materials and existing tiles… … … … 116
4.6 Statistical Analysis… … … … … … … … … … 117
CHAPTER FIVE: CONCLUSION AND RECOMMENDATION
5.1 Conclusion… … … … … … … … … … … 119
5.2 Recommendation… … … … … … … … … … 120
REFERENCES… … … … … … … … … … … 121
APPENDIXES… … … … … … … … … … … 130
xi
CHAPTER ONE
INTRODUCTION
1.1 Background to the study
Recycling is a process of re-using waste materials and converting them into new products to
remove from the waste a potentially useful material. This will reduce the consumption of fresh
raw materials, reduce energy usage, reduce air pollutions (from incineration) and water pollution
(from land filling) thereby reducing the need for “conventional” waste disposal and lower
greenhouse gas emissions produced during plastic production (Lyons and Burford, 1998). A key
component of modern waste reduction and is the third component of the “reduce, reuse, recycle”
waste hierarchy. There are some 150 standards related to recycling of waste such as (ISO
15270:2008) for plastic waste and (ISO 14001: 2004) for environmental management control of
recycling practice.
Recyclable materials include glass, paper, metal, plastic, textiles and e-wastes. Although similar
in effect, the composting or other reuse of biodegradable wastes such as food or garden waste is
not recyclable (Lyon and Burford, 1993). Materials to be recycled are either brought to a
collection center or picked up from the curbside, then sorted, cleaned, and reprocessed into new
materials bound for manufacturing.
In the strictest sense, recycling of materials would produce a fresh supply of the same materials
for example; office paper would be converted into new office paper or used form polystyrene
into new polystyrene. However, this is often difficult or too expensive (compared with
producing the same product from raw materials or other sources). Therefore “recycling” of
many products or materials involves the reuse of produced materials (e.g. paper board) instead.
Another form of recycling is the salvage of certain materials from complex products, either due
to their hazardous nature (e.g. removal and reuse of mercury from various items). Critics dispute
the net economic and environmental benefits of recycling over its costs, and suggest that the
proponents of recycling often make matters worse to their detriment. Specifically, critics argue
2
that the cost and energy used in collection and transportation detract from (and outweigh) the
costs and energy saved in the production process. Also that the product of recycling industry
may be poorer trade compared to the jobs lost in logging mining, and other industries associated
with virgin production, and that materials such as paper pulp can only be recycled a few times
before materials degradation prevents further recycling. Proponents of recycling dispute each of
the claims, and the validity of arguments form both sides has led to enduring controversy.
1.2 Statement of Problems
Plastic wastes are a true menace to our ecosystems and our waste diversion and management
goals. In a typical African society, almost all plastic wastes are barely recyclable, especially
plastic bags used in packaging which are discarded; once discarded, they either enter our
landfills or our water bodies. Plastic wastes once in contact with our water bodies have a
negative impact with ocean economy. Different aquatic lives are being affected by the plastic
debris; for example plastic bags that enter the marine environment break down into smaller
fragments and when consumed affect reproduction in aquatic animals, (Akinro et al., 2012).
The plastic wastes which are highly generated on daily basis in our society is a major constituent
of our municipal wastes, this is problematic because plastic wastes are non-biodegradable and
therefore can stay in the environment for a considerable length of time causing all sorts of
problems. Some people resort to combustion (incineration) as a waste management solution, but
this is not environmentally friendly and sustainable since they can cause environmental pollution
through the release of carbon dioxide, a major contributor to global warming (green house
effect). Landfill with plastic waste is not desirable since plastics are non-biodegradable and no
economic value.
In Nigeria, most drinking water are packaged in plastic bags (sachets) than bottles. The public
have developed a strong taste for such sachet water than the bottle ones since it is portable and
can easily be carried from one place to another and Nigeria being a country with high
entertainment value finds it easier, cheaper and more convenient to use sachet water during
3
events than any other means of portable water. There is also a perception that such sachet water
is cleaner and more mineralized than ordinary tap water. After using the liquid content, the bags
are discarded indiscriminately thereby littering the whole environment. These sachet bags now
constitute a major proportion of the plastic waste generated throughout the country. Also over
the years, plastics have replaced glass and metals as a cheaper and more efficient means of
packaging (IRIN, 2006). Soon after usage, the plastics are randomly discarded. They then
collect around the city, in gutters, threatening small animals, damaging the soil and polluting
beaches. Almost all the major drains in Nigeria are currently flooded with plastic wastes and this
has resulted in floods associated with loss of property and in Nigeria resulted in high rate of
malaria. The whole country is gradually being swallowed up by the plastic waste menace. In
Nigeria, very little has been done in managing the threat posed by plastic waste generation,
hence the earlier the plastic waste menace problem is tackled the better it would be for the
environment and sustainable livelihood.
One of the best options for managing plastic waste is through recycling, because the benefits of
recycling plastic wastes are numerous and it is environmentally friendly compared to the other
methods of waste disposal.
1.3 Objectives of Study
The objectives of the study are:
1. To suggest a method for recycling plastics mixed with sawdust reinforcement for the
production of plastic ceiling tiles.
2. To determine the effect of particle size of reinforcement on the strength properties of
materials.
3. To determine the variation of strength properties within each material.
4. To compare the Engineering properties of the recycled product to that of the existing tiles.
4
1.4 Significance of Study
In a bid to arrest the growing environmental hazards caused by the littering of wastes in Nigeria,
the Federal Government through the Ministry of Environment planned to ban the use of plastic
bags in the country which was supposed to take effect from 1st January 2014 as announced by
the former Minister of Environment Mrs. Hadiza Mailafia (Thisdaylive, 2013). Mailafia said the
plan was to replace the nylon bag with paper bags. She spoke during 2013 world Environment
Day Celebration in Abuja, Nigeria. According to her, government is considering doing away
with the use of sachet water. She explained that the decision to ban plastic bags was necessitated
by the numerous health and environmental hazards associated with its use. According to her
paper bags could easily decompose after being dumped, but plastics bags are non-biodegradable
materials, which could stay in the soil for several years contaminating and destroying the
environment. Regarding the move to stop sachet water production Mailafia said the ministry was
currently conducting research along with experts to finding better alternatives that would replace
water sachets. The above proposed plan to ban water sachet by the Ministry of Environment
raised very strong controversy among the citizens. The civil Liberty Organization (CLO) in
Rivers State opposed the ban through their publicity secretary Mr. Livingstone Wechie during
an interview with the New Agency of Nigeria (NAN) in Port Harcourt; Mr. Livingstone Wechie
said the plan to ban plastics for sachet water would increase unemployment and poverty rates in
the country. He also said that sachet water was an alternative source of portable water to the
common man. Water-borne diseases are very common in the country because of poverty rate,
but the sachet water has reduced it since its inception. A lot of people who were once frustrated
have been empowered through the production and sale of sachet water, Wechie called on the
Federal Government to have a rethink, saying that it should instead devise means of improving
the quality of the water sachets and improve Sanitation to eliminate the litters and environment
hazard posed by sachet water (TheEAGLEonline; 2013). The government of Ivory Coast in an
attempt to reduce pollution banned the use of plastic bags and their Citizens took to the street in
protest claiming about 200,000 families will be put out of work, BBCnewsAfrica (25 November,
2014). Madagascar has also banned the use of plastics, CNN (26 Jan, 2015). Studies are
5
continuously in progress on reusable materials to reduce the cost of production. Polyethene
plastic waste is a common waste in every waste dump and street litters in Nigeria is a thing of
concern. This study will therefore focus on recycling of plastic wastes into ceiling tiles
production, plastics especially sachet water polyethene plastic wastes currently litter everywhere
in Nigeria’s environment. Their successful conversion into other reusable material will lead to
alternative uses thus checking the environment of undue litters.
1.5 Scope of Research
This research focused on the general recycling of all types of plastic wastes which include:
polyethene plastic (sachet water) wastes, table water bottle wastes and different household
plastic containers but due to some limitations in the recycling process, and inability of the water
bottles to be reinforced with sawdust and form a composite material. This study focused more
on recycling of polyethene plastic (sachet water waste) which was more available in quantity for
this study. Recycling of other plastic containers was dropped due to the difficulty in generating
in large recyclable quantity plastic containers with the same plastic identification code.
1.6 Limitation of Study
Plastic is light, easy to store and transport, and are in an endless variety of textures and shapes.
These properties make plastic attractive to manufacturers. Plastics are in almost everything we
touch. It’s used to make our clothes, cars, toys, and household products. Many of the food,
health, and beauty products we enjoy are in plastic packaging. For communities to create a
recycling potential every possible type of plastic packaging is not only daunting, expensive, and
inefficient, it should place all the responsibility and costs on the consumer. For plastic recycling
to work, communities must be able to effectively collect and sort plastics, and manufacturers
must be willing to accept the material for new products. The following limitations were
encountered during this research work:
6
1.6.1 Collection was difficult and expensive
Because plastic is light and bulky in volume, it is difficult to efficiently gather significant
amounts of the same type of plastics. In Nigeria the society is not well organized as to have
drop-off centers where these wastes can be neatly dropped and arranged for collection. The
majority of plastic wastes in Nigeria can be gotten from waste dumps or landfills which
constitute all kinds of wastes including the hazardous ones; therefore this makes collection of
recyclable waste quantity very difficult if not impossible because of the inherent danger
associated with collection of waste.
1.6.2 Extensive sorting is required
There are only seven resin codes, but there are thousands of different types of plastics. Different
combinations of dyes and additives can be added to the basic resin to produce a desired color,
shape, and texture in the final product. These variations in the manufacturing process cause
different melting points within the same resin code. To be made into another product, plastic
must be carefully sorted by type. Combining different types of plastic renders it useless for
manufacturing.
1.6.3 Lack of recycling equipments
Lack of equipment affects every stage of a recycling process; the plastic waste when collected
from waste dumps is dirty and needs to be sorted and washed. Sachet water plastic wastes which
are mainly used in this research work are usually wet and some which are factory reject still in
sachet water form were difficult to shred due to lack of equipment. Drying to remove water to
make it ready for the recycling process was also difficult. During the recycling proper, the use of
box furnace which had a lot of shortcoming among which is release of chemical fumes during
the process. This lack of equipment couldn’t enable us remove the printed ink on the plastic
wastes. Again we were not able to chemically treat the sawdust before use to remove any
available impurity that may hinder its efficiency.
7
1.6.4 Inefficiency of the Recycling Process
The experimental procedure of recycling with Box furnace which was used in this research was
not efficient, apart from release of poisonous choking fumes to the environment. It was also
discovered that some quantities of plastics were being lost during the process of recycling. Some
were lost to evaporation, while others were stuck to walls of the crucible. A good recycling
process as that used at the polyethene recycling workshop of SEDI(Science Equipment
Development Institute), Enugu, Nigeria, had plastic polymer emerging through a nozzle into a
split mould. The quantity of polymer being forced out is carefully controlled, usually by moving
the screw forward in the heated barrel. A series of moulds were used to allow for continual
production during cooling process. This type of production technique is used to produce
moulded products such as plates, bowls, buckets, etc.
1.6.5 Greater Quantity of Waste Needed for Recycling
During this research, challenges were encountered like large heaps of waste plastic when melted
will result to a very small sample which cannot do much for the work. This extended the time of
the project because we had to wait for the table water companies for waste to be generated on
weekly bases instead of sourcing through the waste dumps which have more hazard
IF YOU CAN'T FIND YOUR TOPIC, CLICK HERE TO HIRE A WRITER»
