Waste Hierarchy
The waste hierarchy, also known as the hierarchy of waste management is a nationally and internationally accepted guide for prioritizing waste management practices. It represents the progression of a product or material through the sequential stages of the pyramid of waste management. Standard outline of the hierarchy ranks 6 approaches which are prevention, minimization, reuse, recycle, energy recovery and disposal.
Prevention is to take action first and prevent the generation of waste, i.e. by avoiding its production from the very beginning. For example, we can avoid using disposable goods or single-use materials.
Following prevention is minimization which is to reduce the generation of waste. For example, we can select items with the least packaging or buy products that are recycled, recyclable, repairable, refillable, re-usable or biodegradable.
Where avoiding and reducing waste is not possible, the next most preferred option is to re-use the materials without further processing, avoiding the costs of energy and other resources required for recycling. For example, many household and industrial items can be repaired, re-used, sold or donated to charities.
When reuse is not an option, then recycle kicks in. The difference between recycle and reuse is that recycle break an item down to its raw materials which can be further made into new items. In the milk bottle example, reuse is washing and refilling the bottle, whilst recycle is grinding the glass bottle, melting it and turning the raw material into a new glass based items.
Where further recycling is not feasible, it may be possible to recover the energy from the material. Energy recovery makes use of the calorific value of waste, which helps reduce the use of fossil fuels like coal or oil and as result reduce mission of CO2 from the burning of fossil fuels. Without this energy recovery technology, non-recyclable refuse would simply end up in disposal.
The final action is disposal in landfills or through incineration without energy recovery. This is the last resort method for waste disposal and the least favored when the above five options have been tried.
The aim of the waste hierarchy is to extract the maximum practical benefits from products and to generate the minimum amount of waste, achieving the optimal environmental outcomes. Proper application of the waste hierarchy can help prevent emissions of greenhouse gases, reduces pollutants, save energy, conserves resources, create jobs and stimulate the development of green technologies.
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