Landfill disposal packaging plastics

Because of their low density, plastics comprise approximately 20% by volume of landfilled solid waste, although they contribute only about 7% of the total weight. Public opposition limits the disposal of plastics via incineration, despite their comparatively high energy content. These factors have stimulated considerable interest in the development of biodegradable plastics as replacements for conventional plastics, particularly in packaging and disposable applications. 

Interest in environmentally degradable polymers began more than thirty years ago, when it was first recognized that the commonly used commodity packaging plastics such as polyolefins, poly(vinyl chloride, polystyrene, and poly(ethylene terephthalate) were accumulating in the environments in which they were discarded, after use. Since these polymers were developed for their resistance properties, it should not have been surprising that they were recalcitrant in landfills and as litter when disposed of in a negligent manner. 

It follows that there are three reasons why the use of degradable plastics in place of conventional packaging plastics in landfill disposal is encouraged by both financial and environmental considerations. 

A major difficulty is that so many applications employ polymers as though they were readily disposable, despite the fact that they are, in reality, among the more inert of chemical pollutants. In particular, plastic packaging tends to make a single use of a fabricated polymer which is then thrown away. Even when disposed of responsibly, packaging materials are the source of a serious pollution problem. Municipal authorities dispose of such materials by one of two routes, landfilling and incineration, of which the latter cannot be readily used for chlorinated polymers, such as PVC, because of the additional problems caused by organochlorine species in the atmosphere. 

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