Bin bag
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Plastic bags are a convenient and sanitary way of handling rubbish, and are widely used. Plastic rubbish bags are fairly lightweight and are particularly useful for messy or wet rubbish, as is commonly the case with food waste, and are also useful for wrapping up rubbish to minimize odor. Plastic bags are often used for lining litter or waste containers or bins. This serves to keep the container sanitary by avoiding container contact with the rubbish. After the bag in the container is filled with litter, the bag can be pulled out by its edges, closed, and tied with minimal contact with the waste matter.
Plastic bags for rubbish or litter are sold in a number of sizes at many other stores in packets or rolls of a few tens of bags. Wire twist ties are sometimes supplied for closing the bag once full. In the mid-1990s rubbish bags with draw strings for closure were introduced. Some bags have handles which may be tied, or holes through which the neck of the bag can be pulled. Most commonly, the rather soft, flexible plastic used to make rubbish bags is LDPE (Low Density Polyethylene) or, for strength, LLDPE (Linear Low Density Polyethylene). HDPE (High Density Polyethylene) is sometimes used. == Created in 1950, this invention can be attributed to Canadians Harry Wasylyk, Larry Hansen and Frank Plomp. In a recent special on CBC television, the green garbage bag ranked 36th among the top 50 Canadian inventions.[1]
Plastic bags can be incinerated with their contents in appropriate facilities for waste-to-energy conversion. They are stable and benign in sanitary landfills.
Biodegradable plastic bags
Some bags are made of biodegradable polythene film. These will decompose when exposed to air, sun, and moisture or submitted for composting. They do not readily decompose in a sealed landfill. They are also considered a possible contaminant to plastic recycling operations.
Oxo-biodegradable and other degradable plastic bags have certain useful applications when used as rubbish bags. Organic waste can be put into oxo-biodegradable plastic sacks and put straight into the composting plant, unopened, thus reducing smells, disease transmission by insects, and handling hazards. The resulting compost may be used by farmers and growers. Since oxo-biodegradable plastic (unlike the starch-based alternative) releases its carbon slowly, it produces high quality compost. Oxo-biodegradable plastic does not degrade quickly in low temperature "windrow" composting, but it is suitable for "in-vessel" composting at the higher temperatures required by new animal by-products regulations. Oxo-biodegradable plastics become peroxidised and embrittled, and behave like natural waste. It is bio-assimilated by the same bacteria and fungi, which transform the degraded plastic products to cell biomass, like lignocellulosic materials. Oxo-biodegradable plastic is designed to fragment by a process which includes both photo-oxidation and thermo-oxidation, so it can degrade in the dark.
References
Books
- Brody, A. L., and Marsh, K, S., "Encyclopedia of Packaging Technology", John Wiley & Sons, 1997, ISBN: 0-471-06397-5
- Selke, S, "Packaging and the Environment", 1994, ISBN: 1566761042
- Selke, S,. "Plastics Packaging", 2004, ISBN: 1569903727