In some cases, the cost of recyclable materials also exceeds the cost of raw materials. Virgin plastic resin costs 40 percent less than recycled resin. Additionally, a United States Environmental Protection Agency (EPA) study that tracked the price of clear glass from July 15 to August 2, 1991, found that the average cost per ton ranged from $40 to $60, while a USGS report shows that the cost per ton of raw silica sand from years 1993 to 1997 fell between $17.33 and $18.10.
It is difficult to determine the amount of energy consumed or produced in waste disposal processes in broader ecological terms, where causal relations dissipate into complex networks of material and energy flow. For example, "cities do not follow all the strategies of ecosystem development. Biogeochemical paths become fairly straight relative to wild ecosystems, with very reduced recycling, resulting in large flows of waste and low total energy efficiencies. By contrast, in wild ecosystems, one population’s wastes are another population’s resources, and succession results in efficient exploitation of available resources. However, even modernized cities may still be in the earliest stages of a succession that may take centuries or millennia to complete.":720 How much energy is used in recycling also depends on the type of material being recycled and the process used to do so. Aluminium is generally agreed to use far less energy when recycled rather than being produced from scratch. The EPA states that "recycling aluminum cans, for example, saves 95 percent of the energy required to make the same amount of aluminum from its virgin source, bauxite." In 2009 more than half of all aluminium cans produced came from recycled aluminium.
Legislation has also been used to increase and maintain a demand for recycled materials. Four methods of such legislation exist: minimum recycled content mandates, utilization rates, procurement policies, recycled product labeling.
The wheelie bin is a waste container on wheels designed to make it easier for users to transport heavy loads of refuse to the curb or other pick-up point. George Dempster invented the Dempster-Dumpster system in the 1930s for automatically loading the contents of standardized mobile steel containers onto the dustcart. This led to the classic Dempster Dumpmaster waste collection vehicle of the 1950s, but wheelie bins did not become commonplace until the 1970s. The term dumpster is frequently used as a generic term for a large MGB or the non-mobile variety (known as a skip in the UK or Australia) in the United States. composteur maison
In the US residential wheelie bins are also generically called "Herbie Curbies." The modern bin is a German invention of the 1970s in a patent held by Schneider, and licensed to other companies outside Germany.