Additionally, there are groups of three containers used to collect the small proportions of materials [yellow for packages of plastic and metal, blue for paper and green for glass] which are located near residential areas, schools, parks, sports centers, and markets. All of them exceptional improve the efficiency of recovery of waste in the Oporto region. After the papers are collected separately, the different varieties of papers can be put into different systems to reuse. Incineration or landfill system have been the main ways to manage the paper before, however world wide paper recycling has been improving since 1986, a particular paper recycling industry has become to be used. One example, in Egypt, a great deal of old newspaper and old magazines are collected, and then go through the beater' and the air injection flotation cell' to produce a pulp of optical and physical properties which is acceptable to be reuses in newsprint. Paper recycling industry usage in modern society leads paper recycling to become scientific and unpolluted. (Ravindra et al, 2001).
The second major waste from households recycled in modern society is plastic. Plastic is a wonder-material with a wide range of characteristics and qualities. Plastic are lightweight and durable. They are resistant to moisture and decay. The range of products and processes that use plastic is vast. (Environment Council, 2000: 2,103) Nevertheless, by the chemic reasons of plastics, plastic is considered by people as one of the most difficult materials to recycle. In addition, legislative pressures and public resistance to dumping close to areas of habitation, plastic deposal in landfill has become slightly unpopular. These factors are leading people to look for unpolluted and high efficiency way to dispose plastic. Currently, there are several main methods by which plastics are recycled, however, none of them are suitable for every genus of plastics.