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.
Many economists favor a moderate level of government intervention to provide recycling services. Economists of this mindset probably view product disposal as an externality of production and subsequently argue government is most capable of alleviating such a dilemma.
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.
The amount of energy saved through recycling depends upon the material being recycled and the type of energy accounting that is used. Emergy (spelled with an m) analysis, for example, budgets for the amount of energy of one kind (exergy) that is required to make or transform things into another kind of product or service. Using emergy life-cycle analysis researchers have concluded that materials with large refining costs have the greatest potential for high recycle benefits. Moreover, the highest emergy efficiency accrues from systems geared toward material recycling, where materials are engineered to recycle back into their original form and purpose, followed by adaptive reuse systems where the materials are recycled into a different kind of product, and then by by-product reuse systems where parts of the products are used to make an entirely different product.
The smaller wheelie bins, for domestic or light commercial use, typically hold 120 to 360 litres (26 to 79 imp gal; 32 to 95 US gal), with 240 litres (53 imp gal; 63 US gal) being the most common. They have a hinged flap lid and two wheels on the bottom on the same side as the lid hinge. There is a bar behind the hinge on the top of the bin which is used to move it, or to hoist it up onto a garbage truck for emptying. Industrial waste The 240 litre bin is usually considered to have the same capacity as three traditional waste containers. In the UK, "wheelie bins" for non-recyclable domestic waste are currently collected either weekly or once a fortnight, depending on the local Council's waste management policies.