Plastic Waste Management & Plastic Recycling – Methods & Options
Less than 20% of plastic waste can be recycled by simple remolding. However 80% of the plastic waste generated can be recycled only through Pyrolysis & Hydrolysis. Plastics recycling technologies have been divided into three general types primary, secondary tertiary and Quaternary. Primary and secondary method of recycling are physical methods of plastic recycling, whereas tertiary method of recycling is chemical method of plastic recycling. Quaternary method of recycling is combustion of plastic waste which is not allowed in most of the developed and developing countries.
Primary recycling:
This is a physical method of plastic recycling. Primary recycling involves processing of a waste/scrap into a product with characteristics similar to those of original product. Remoulding is an example of this process. Multi-layered and mixed plastic waste cannot be recycled using this process. Only segregated plastic waste can be recycled using this process.
Secondary recycling:
This is a physical method of plastic recycling. Secondary recycling involves processing of waste/scrap plastics into materials that have characteristics different from those of original plastics product. Multi-layered and mixed plastic waste cannot be recycled using this process. Only segregated plastic waste can be recycled using this process.
Tertiary recycling:
This is a chemical method of recycling plastic waste. Tertiary recycling involves the production of basic chemicals and fuels from plastics waste using pyrolysis of hydrolysis as a process. This method of recycling it suitable for all types of plastic waste including the multi-layer plastic waste for which first two methods of recycling are not suitable. 80% of plastic waste generated these days cannot be recycled using primary or secondary method of recycling. Hence, tertiary method of recycling is the only sustainable method for disposal of this 80% of plastic waste. This method of recycling allows us to recover the energy from plastic waste without burning the plastic waste.
Quaternary recycling:
This method retrieves the energy content of waste/scrap plastics by burning/incineration. The problem with this process is generation of very high levels of pollution including emission of harmful chemicals like dioxane and furans. This process is not in use in India. Also burning and incineration of plastic is banned in most of the developed countries.