The quantum of solid waste is ever increasing due to increase in population, developmental activities, changes in life style, and socio-economic conditions, Plastics waste is a significant portion of the total municipal solid waste (MSW).
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Environmental Issues and Challenges
It is estimated that approximately 10 thousand tons per day (TPD) of plastics waste is generated i.e. 9% of 1.20 lacs TPD of MSW in the country.
Types of Plastic Waste
The plastics waste constitutes two major categories of plastics;
(i) Thermoplastics
Thermoplastics, constitutes 80% and thermoset constitutes approximately 20% of total post-consumer plastics waste generated in India. The Thermoplastics are recyclable plastics.
Eg: Polyethylene Terephthalate (PET), Low Density Poly Ethylene (LDPE), Poly Vinyal Chloride (PVC), High Density Poly Ethylene (HDPE), Polypropylene (PP), Polystyrene (PS) etc.
(ii) Thermoset plastics
Thermoset plastics contains alkyd, epoxy, ester, melamine formaldehyde, phenolic formaldehyde, silicon, urea formaldehyde, polyurethane, metalised and multilayer plastics etc.
The environmental hazards due to mismanagement of plastics waste include the following aspects:
- Littered plastics spoil beauty of the city and choke drains and make important public Places filthy;
- Garbage containing plastics, when burnt may cause air pollution by emitting polluting Gases;
- Garbage mixed with plastics interferes in waste processing facility and may also cause Problems in landfill operations;
- Recycling industries operating in non-conforming areas are posing unhygienic Problems to the environment.
Main Features of the Plastics Manufacture and Usage (Amendment) Rules, 2003
Regulation of plastics waste, particularly manufacture and use of recycled plastics carry bags and containers is being regulated in the country as per “Recycled Plastics Manufacture and Usage Rules, 1999 and as amended in 2003. According to these Rules:
1.No person shall manufacture, stock, distribute or sell carry bags made of virgin or recycled plastic bags which are less than 8 x 12 inches in size and having thickness less than 20 microns.
2. No vendor shall use carry bags/containers made of recycled plastics for storing, carrying, dispensing or packaging of food stuffs
3. Carry bags and containers made of recycled plastic and used for purposes other than storing and packaging food stuffs shall be manufactured using pigments and colorants as per ISO 9833:1981 entitled “List of pigments and colorants for use in plastics in contact with food stuffs, pharmaceuticals and drinking water”
4. Recycling of plastics shall be undertaken strictly in accordance with the Bureau of Indian Standard specification: IS 14534:1998 entitled “The Guidelines for Recycling of Plastics”
5. Manufacturers of recycled plastic carry bags having printing facilities shall code/mark carry Bags and containers as per Bureau of Indian Standard specification: IS 14534:1998 (The Guidelines for Recycling of Plastics).
6. No person shall manufacture carry bags or containers irrespective of its size or weight unless the occupier of the unit has registered the unit with respective SPCB/PCC prior to the commencement of production.
7. The prescribed authority for enforcement of the provisions of these rules related to manufacturing and recycling is SPCB in respect of States and the PCC in Union Territories and for relating to use, collection, segregation, transportation and disposal shall be the District Collector/ Deputy Commissioner of the concerned district
Options for Plastic Waste Management
Recycling of plastics through environmentally sound manner
Recycling of plastics should be carried in such a manner to minimize the pollution during the process and as a result to enhance the efficiency of the process and conserve the energy. Plastics recycling technologies have been historically divided into four general types -primary, secondary, tertiary and quaternary.
• Primary recycling involves processing of a waste/scrap into a product with characteristics similar to those of original product.
• Secondary recycling involves processing of waste/scrap plastics into materials that have characteristics different from those of original plastics product.
• Tertiary recycling involves the production of basic chemicals and fuels from plastics waste/scrap as part of the municipal waste stream or as a segregated waste.
• Quaternary recycling retrieves the energy content of waste/scrap plastics by burning/incineration. This process is not in use in India.
Steps Involved in the Recycling Process
1.Selection: The recyclers / reprocessors have to select the waste / scrap which are suitable for recycling /reprocessing.
2.Segregation: The plastics waste shall be segregated as per the Codes 1-7 mentioned
3.Processing: After selection and segregation of the pre-consumer waste (factory waste) shall be directly recycled. The post consumer waste (used plastic waste) shall be washed, shredded, agglomerated, extruded and granulated
Polymer Coated Bitumen Road
The CPCB has undertaken a project in collaboration with Thiagarajar College of Engineering Madurai to evaluate the performance of polymer coated built roads laid during 2002-2006 in different cities.
The observations are as below:
- The coating of plastics over aggregate improves Impact, Los Angels Abrasion and Crushing Value with the increase in the percentage of plastics.
- The extracted bitumen showed almost near value for Marshall stability.
- The entire road was having good skid resistance and texture values.
- All the stretches in the roads have been found reasonably strong.
- The unevenness index values of these roads are nearly 3000 mm/km, which indicate a good surface evenness.
- The plastic tar roads have not developed any potholes, rutting, raveling or edge flaw, even though these roads are more than four years of age.
- Polymer coated aggregate bitumen mix performs well compared to polymer modified bitumen mix.
- Higher percentage of polymer coating improves the binding strength of the mix.
- Foam plastics have better binding values.