waste management of plastics

WASTE MANAGEMENT OF PLASTICS MATERIAL
Mrs.G.D.SHAH (M.E. POLYMER TECH.)
I/C HEAD OF PLASTICSENGG.DEPT.
GOVT. POLYTECHNIC, AHMEDABAD
GUJARAT, INDIA.
The World Environment Day is observed on 5th June every year, to conserve our environment. Plastic waste remains one of the biggest headaches globally. Piles of plastic waste have become a common site in towns, and the menace is rapidly spreading to the countryside. Plastics have become an indispensable part of our daily life. But repeated reprocessing of plastic waste, and its disposal creates environmental problems, pose health hazards, although plastics pose a hazard to the environment because they do not decay, plastics are preferred because they are cheap and versatile.
Health impacts of solid waste
The unhygienic use and disposal of plastics and its effects on human health has become a matter of concern. Colored plastics are harmful as their pigment contains heavy metals that are highly toxic. Some of the harmful metals found in plastics are copper, lead, chromium, cobalt, selenium, and cadmium. In most industrialized countries, colour plastics have been legally banned. Until recently no legislation was framed to deal specifically with issues connected with plastic waste management. The Government of Himachal Pradesh was one of the earliest to introduce legislation prohibiting the throwing or disposing of plastic articles in public places. The Union Ministry of Environment and Forests has recently notified the "Recycled Plastic Manufacture and Usage Rules, 1999''. These rules require that carry bags or containers used for purposes of storing shall be made of virgin plastic and be in natural shade or white. These items when made of recycled plastic and used for purposes other than storing and packaging of foodstuffs shall use pigments and colorants as per Indian Standards. Recycling of plastics shall also be undertaken strictly in accordance with specifications prescribed by the Bureau of Indian Standards, and shall carry a mark that the product is manufactured out of recycled plastic. The thickness of carry bags shall not be less than 20 microns. Finally and most importantly, Rule 4 prohibits all vendors from using carry bags or containers made out of recycled plastics for storing, carrying, dispensing or packaging of foodstuffs. In other words all vendors are required to use carry bags and containers manufactured to specifications prescribed in the 1999 Rules.
Sorting Of Wastes
Waste is separated into the following categories:

1. kitchen wastes
2. paper and cardboard
3. glass
4. aluminium
5. other metals
6. oils, fuels, other liquids
7. wood
8. batteries
9. other materials, plastics, construction materials and obsolete items

Preventive measures
Proper methods of waste disposal have to be undertaken to ensure that it does not affect the environment around the area or cause health hazards to the people living there. At the household-level proper segregation of waste has to be done and it should be ensured that all organic matter is kept aside for composting, which is undoubtedly the best method for the correct disposal of this segment of the waste. In fact, the organic part of the waste that is generated decomposes more easily, attracts insects and causes disease. Organic waste can be composted and then used as a fertilizer.
Waste Disposal Options:
Plastics material offer many waste disposal options because they are usually solid, handleable materials. They are recoverable in most cases after use for several disposal options. This includes:
1. Incineration
2. Recycling
3. Land fill
4. Composting
5. Reuse
6. Source of energy
7. Reclamation
Incineration
Qualified staff operate high-temperature two-chamber incinerators at all stations. Incinerator ash and residues are returned to disposal. Kitchen and medical waste, low grade paper and cardboard, contaminated low density polythene (rubbish bags) and solid human waste from field camps are incinerated. All fats and oils, plastics (including polyurethane foam, polystyrene), large quantities of timber boxing and out-of-date food are returned for waste management.
Disadvantages of incineration:
1. Incineration destroys valuable resources.
2. Burning fossil fuels like coal, oil and gas is causing increasing levels of carbon dioxide in our atmosphere, leading to climate change. Incineration contributes to climate change, because when materials are burnt more fossil fuel energy is used to replace them through mining, manufacturing, and transportation around the world. Energy from burning waste is not renewable.
3. Incinerators need a steady stream of waste to keep them going. This means there is no incentive to reduce waste or recycle it.
4. Incineration causes pollution from air emissions and toxic ash.
5. Incineration is worse for climate change than recycling because new products have to be made to replace those destroyed.
6. Incineration does not provide the thousands of new job opportunities that recycling does.
Re-Cycling
Many items are re-used on station, e.g. packing materials such as cardboard boxes and plastic sheeting, packing crate timber, 200 L drums either with the lid part opened (for metal waste, glass or incinerator ash) or intact for returning chemical waste (e.g. photographic chemicals). Official photography on stations is now substantially electronic (i.e. no wet processing). All stations sort wastes as indicated above for disposal to recyclers. Recycling is one of the most immediate and effective ways to protect the environment. By recycling instead of producing goods from raw materials, substantial amounts of energy and raw materials are saved. 40% of local authorities now provide facilities for recycling plastics, with a quarter of these involved in doorstep collection schemes which are the most successful in recovering plastic waste. The six most common types of plastic can all easily be recycled and have a much higher value than most recyclable materials. As the volume of recycled material increases markets will expand, making the material more attractive to industry and the benefits of recycling more apparent. Recycling and waste minimization businesses could employ over 100,000 more people than the landfill and incinerator businesses would make redundant. Hence we can:
• Buy products made of recycled plastic wherever possible.
• Recycle plastic plants can be established.
• Set up a community scheme. The Community Recycling Network can help
• Encourage recycling in your workplace/school/church, etc.
Landfill:
Friends of the Earth wants a ban on new landfill capacity until policies are in place to achieve the 60-80 per cent recycling rates achieved in other countries, because:
• Landfill waste valuable resources.
• Landfill contributes to climate change, because when materials are buried more fossil fuel energy is used to replace them through mining, manufacturing, and transportation around the world.
• Landfill produces methane, a powerful greenhouse gas which contributes to climate change.
• Landfill creates water pollution as liquid from landfill sites leaks into our water supply.
• Landfill can lead to land contamination.
• Landfill leads to increased traffic, noise, smell, smoke, dust and litter.
Composting:
Composting is predominantly biodegradation with the possibility of oxidation and hydrolysis. There is an opportunity for environmentally degradable plastics which are used in food application such as wrappers and utensils in these uses, plastics are contaminated with food residues and are suitable for composting without separation. Where recovery of current plastics is not economically feasible, viable, controllable or attractive, the plastics remain as litter and may be discarded at sea from naval vessels, may be used in farm and agricultural application such as pre emergency plant protection or in hygienic application such as diapers, hospital garments and swabs etc.
Re-use
It makes sense and it saves energy to re-use rather than recycle, but it is currently more economical for manufacturers to produce new product rather than wash and re-fill packaging. The Body Shop will re-fill plastic bottles with the same product, and many small producers across the country also do this, showing that re-use can make economic sense.
• Re-use plastic bags, or better still avoid them by using a sturdy bag that will last for years.
• Re-use pots with lids for storage rather than buying new ones.
• In the garden, re-use plastic pots for raising seedlings and cut-down plastic bottles to protect them from slugs
• Give usable goods to charity shops, or hold car boot sales for charity with any plastic items that can be re-used.
• Ask suppliers if they will take back plastic items for re-use: for example, plant pots in garden centers.
• Use refillable toner cartridges.
A Source of Energy
Material recovery is by no means the only way to recycle plastics. Another option is to recover their thermal content, providing an alternative source of energy. An average typical value for polymers found commonly in house hold waste is 38 mega joules per kilogram (MJ/kg), which compares favorably to the equivalent value of 31 MJ/kg for coal. This represents a valuable resource raising the overall calorific value of domestic waste which can then be recovered through controlled combustion and re-used in the form of heat and steam to power electricity generators. Successful ventures in this field include plants, such as a major incinerator, which produces steam to power an electricity turbine. Waste containing plastics can also be reprocessed to yield fuel pellets, which have the added advantage of being storable.
It is sometimes claimed that incineration of municipal waste poses an environmental problem in the shape of atmospheric pollutants. Although the potential is there, modem incineration techniques ensure that actual emission levels are kept with-in internationally accepted safety limits. In fact, several countries, such as Sweden, Germany and the Netherlands, have recently affirmed their confidence in incineration by announcing plans to expand existing capacity.
Reclamation
The majority of municipal waste is still used as land fill, due to the very high cost of facilities for the sorting, separation and recycling of waste. As plastics are stable, both physically and chemically they in turn provide stability to the tips. This provides a safe and solid foundation upon which to build; thereby releasing land for development.
Conserving the Environment
The plastics industry is concerned that it should take appropriate care of resources and the environment. The advantages of plastics over other raw materials are apparent from the beginning of their life-cycle. Research shows that it often takes less energy to make products in plastics, and although most plastics depend on oil, coal or gas they are responsible for only a small fraction of the national consumption of these fuels. Energy savings can be made easily with plastics because plastics are lighter, easier to store and transport. Also the developments in the recycling of plastics, there are interesting advances in the production of degradable plastics for products which need only a limited life.
The Future
Plastics recycling are in the growth phase as the whole industry is still relatively young. A further development in recycling, which is being researched, is the recovery of the individual chemical components of plastics for re-use as chemicals, or for the manufacture of new plastics.