Recycling is the process of converting waste materials into new materials and objects. The recyclability of a material depends on its ability to reacquire the properties it had in its virgin state. It is an alternative to "conventional"
waste disposal that can save material and help lower greenhouse gas emissions.
Recycling can prevent the
waste of potentially useful materials and reduce the consumption of fresh raw materials, thereby reducing: energy usage,
air pollution (from incineration), and water
pollution (from landfilling). There are two broad types of
recycling operations: internal and external. Internal
recycling is the reuse in a manufacturing process of materials that are a
waste product of that process. Internal
recycling is common in the metals industry, for example. The manufacture of copper tubing results in a certain amount of
waste in the form of tube ends and trimmings; this material is remelted and recast. Another form of internal
recycling is seen in the distilling industry, in which, after the distillation, spent grain mash is dried and processed into an edible foodstuff for cattle. External
recycling is the reclaiming of materials from a product that has been worn out or rendered obsolete. An example of external
recycling is the collection of old newspapers and magazines for repulping and their manufacture into new paper products. Aluminum cans and glass bottles are other examples of everyday objects that are externally recycled on a wide scale. These materials can be collected by any of three main methods: buy-back centres, which purchase
waste materials that have been sorted and brought in by consumers; drop-off centres, where consumers can deposit
waste materials but are not paid for them; and curbside collection, in which homes and businesses sort their
waste materials and deposit them by the curb for collection by a central agency.
Relevant Topics in Medical Sciences
