Waste management is the collection, transport, processing, recycling pelacur or disposal of waste materials, usually ones produced by human activity, in an effort to reduce their effect on human health or local aesthetics or amenity. A subfocus in recent decades has been to reduce waste materials' effect on the natural world and the environment and to recover resources from them.
Waste management can involve solid, liquid or gaseous substances with different methods and fields of expertise for each.
Waste management practices differ for developed and developing nations, for urban and rural areas, and for residential, industrial, and commercial producers. Waste management for non-hazardous residential and institutional waste in metropolitan areas is usually the responsibility of local government authorities, while management for non-hazardous commercial and industrial waste is usually the responsibility of the generator.
Waste management concepts
The waste hierarchy refers to the "3 Rs" reduce, reuse and recycle, which classify waste management strategies according to their desirability in terms of waste minimization. The waste hierarchy remains the cornerstone of most waste minimisation strategies. The aim of the waste hierarchy is to extract the maximum practical benefits from products and to generate the minimum amount of waste.
Waste hierarchyExtended Producer Responsibility (EPR) is a strategy designed to promote the integration of environmental costs associated with products throughout their life cycles into the market price of the products. Extended producer responsibility imposes accountability over the entire life cycle of products and packaging introduced on the market. This means that firms which manufacture, import and/or sell products are required to be financially or physically responsible for such products after their useful life.
Polluter pays principle
Waste collection methods vary widely between different countries and regions, and it would be impossible to describe them all. Many areas, especially those in less developed countries, do not have a formal waste-collection system in place.
For example, in Australia most urban domestic households have a 240-litre (63.4 U.S. gallon) bin that is emptied weekly from the curb using side- or rear-loading compactor trucks. In Europe and a few other places around the world, a few communities use a proprietary collection system known as Envac, which conveys refuse via underground conduits using a vacuum system. Roosevelt Island has had this system since 1975. In Canadian urban centres curbside collection is the most common method of disposal, whereby the city collects waste and/or recyclables and/or organics on a scheduled basis. In rural areas people usually dispose of their waste by hauling it to a transfer station. Waste collected is then transported to a regional landfill.
Waste collection methods
Waste management methods for vary widely between areas for many reasons, including type of waste material, nearby land uses, and the area available.
Waste management methods
Disposing of waste in a landfill is one of the most traditional method of waste disposal, and it remains a common practice in most countries. Historically, landfills were often established in disused quarries, mining voids or borrow pits. A properly-designed and well-managed landfill can be a hygienic and relatively inexpensive method of disposing of waste materials in a way that minimises their impact on the local environment. Older, poorly-designed or poorly-managed landfills can create a number of adverse environmental impacts such as wind-blown litter, attraction of vermin, and generation of leachate where result of rain percolating through the waste and reacting with the products of decomposition, chemicals and other materials in the waste to produce the leachate which can pollute groundwater and surface water. Another byproduct of landfills is landfill gas (mostly composed of methane and carbon dioxide), which is produced as organic waste breaks down anaerobically. This gas can create odor problems, kill surface vegetation, and is a greenhouse gas.
Design characteristics of a modern landfill include methods to contain leachate, such as clay or plastic lining material. Disposed waste is normally compacted to increase its density and stablise the new landform, and covered to prevent attracting vermin (such as mice or rats) and reduce the amount of wind-blown litter. Many landfills also have a landfill gas extraction system installed after closure to extract the landfill gas generated by the decomposing waste materials. Gas is pumped out of the landfill using perforated pipes and flared off or burnt in a gas engine to generate electricity. Flaring off the gas is generally a better environmental outcome than allowing it to escape to the atmosphere, as this consumes the methane (which is a far more potent greenhouse gas than carbon dioxide).
Many local authorities, especially in urban areas, have found it difficult to establish new landfills due to opposition from owners of adjacent land. Few people want a landfill in their local neighborhood. As a result, solid waste disposal in these areas has become more expensive as material must be transported further away for disposal (or managed by other methods).
This fact, as well as growing concern about the impacts of excessive materials consumption, has given rise to efforts to minimise the amount of waste sent to landfill in many areas. These efforts include taxing or levying waste sent to landfill, recycling the materials, converting material to energy, designing products that use less material, and legislation mandating that manufacturers become responsible for disposal costs of products or packaging. A related subject is that of industrial ecology, where the material flows between industries is studied. The by-products of one industry may be a useful commodity to another, leading to a reduced materials waste stream.
Some futurists have speculated that landfills may one day be mined: as some resources become more scarce, they will become valuable enough that it would be economical to 'mine' them from landfills where these materials were previously discarded as valueless. A related idea is the establishment of a 'monofill' landfill containing only one waste type (e.g. waste vehicle tires), as a method of long-term storage.
Landfill
Incineration
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