Project Name : Waste management and recycling
Project Theme: Industry
Objective/Aim: Lifestyle changes in the modernized world have brought about a new era of waste generation. Waste management and recycling of resources has become the need of the hour. An exposure visit to the dumping ground of Chandigarh triggered questions in our mind regarding the recycling of waste PET bottles. The use and throw plastic bottles in our water and cold drink industry is a major concern to the environmentalist. In fact 500,000 billion plastic bottles are thrown away each year across the world. Each bottle takes around 700 years to start to decompose and about 1000 years to get decomposed completely.
The aims/objectives of our project are:
To find a process that recycles PET bottles and reduces the load of solid waste on our planet.
To propose a design for a textile spinning mill that produces polyester by recycling PET bottles thus, reducing the cost of production and conserving raw materials (PET) used.
Scientific Principle Involved: Polyester, a common synthetic fibre used in the textile industry, is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term “polyester” as a specific material most commonly refers to polyethylene terephthalate (PET). PET consists of polymerized units of the monomer ethylene terephthalate, with repeating C10H8O4 units.
The PET bottles used in beverages industry, being non-biodegradable add to the waste on the planet. But, since the bottles and polyester fiber belong to the same parent compound, the PET bottles can be recycled or re- polymerised to form polyester fiber. This reduces the cost of production in a polyester spinning industry and
helps conserve raw materials (PET).
Material Used: Plywood (for base), used thermocol sheets, used tins, bottles, paper cups, transparency sheet, PVC pipes, broken toys, 6V battery, switch, wire, paint, etc.
Working Investigation/ Findings: PET used in the bottling industry amounts to about 30% of the total PET produced, while that used in textile polyester production is about 65% as shown in the table below:
This 30% can be recycled into the textile industry by a simple process:
The process involves the following steps:
1. Collection of waste bottles
2. Cleaning them (washing with caustic soda at 90º-95ºC)
3. Crushing them to produce PET flakes
4. Drying them to remove moisture (as PET is hygroscopic and absorbs moisture from the atmosphere) using a Vacuum drier at 180ºC for 5-6 hours.
5. Gradual heating and melting in an extruder (260º-280ºC) (POLYMERISATION)
6. Forming synthetic PET fibres by passing through spinerette (4 denier)
7. Drawing and stretching them to produce thin fibres with the desired tenacity (1.5 denier)
8. Crimping them to avoid tangling of fibres
9. Cutting them to a pre-defined length
10. Spinning them on spinning mills to produce polyester yarn
The main advantages of this process:
1. This reduces cost of production as used PET bottles are cheaper than buying textile PET from market source.
2. It recycles PET (used in bottles), thus helping in solid waste management and keeping the earth clean and green by saving landfill space, reducing greenhouse emissions and conserving oil needed to produce virgin PET.
3. PET used in beverage bottles is of a very good, food grade quality. This, in turn improves the quality of yarn produced.
4. Recycling waste properly helps improve health and economic conditions of waste collectors. Utility and Further Scope of the Project: The project finds immense utility in the textile industry. Recycling PET reduces the demand for virgin PET production. The caps that are removed from bottles can also be recycled to get coarse fiber that can be used for making carpets, mats, blankets etc. It can also be used to make other PET products like toys, pens etc.
Increased awareness about PET recycling can help in organized collection, sorting at source and ensure a continuous supply of bottles to the mill.
Name of the School: The Millenium School, Mohali (Punjab)
