The hierarchy of Integrated Solid Waste Management (ISWM) primarily aims to evaluate all waste management steps as a whole in order to ensure sustainability in both environmental and economic terms.
According to this model, prevention and reduction of waste at the level of source is ideally the first step in waste management.
In certain cases where the generation of waste is inevitable, the next stage of reuse and recycling are applied. Furthermore, for the type of waste products for which recycling is not possible, regular landfilling is carried out.
Steps in Solid Waste Management Hierarchy
The steps in ISWM in the descending order of preference and importance are :
Reduce
Communities are encouraged to take measures to reduce the amount and toxicity of the waste generated by them. One of which may be to limit the possible spread of contamination by sealing access points to the sewer or water system with drain covers. The most important part is that the planning and preparation efforts each to minimize the amount and toxicity of incident-generated waste have several environmental benefits (e.g., reducing the number of new materials needed to rebuild) and economic benefits (e.g., shortening the recovery timeline) as well.
Reuse
the term essentially includes materials that can be used again in their original form. To maximize the reuse opportunities for different materials, a viable reuse infrastructure such as end markets for salvaged products, should be in place prior to the initiation of the process. In addition, organisations should establish and document guidelines in their waste management plans for salvaging and reusing various materials. Risk communication should be a primary part of waste-related community outreach plans to help ensure public acceptance of the salvaged materials and promote reuse of products.
Recycle
This process reduces the need to extract raw materials from the ground or to import them. Producing metals, glass and paper from waste materials rather than raw materials consumes far less energy and resources and generates less waste for landfill, giving further reductions in pollution. Recycling enables us to prevent excessive consumption of non-replenishable, thereby helping in conserving and preventing these resources from getting exhausted.
Recovery
it is the process of recovery of waste without any pre-processing. For a better understanding let us take an example. Waste oils which cannot possibly be refined for reuse in vehicles can be burnt for energy thereby leading to energy recovery, therefore this recovery of energy reduces our dependence on coal and imported oil which are non-replenishable sources of energy.
Disposal
As a final step in waste management, disposal is the least preferred option when no other procedure is possible. In this step, the waste material is deposited in a registered landfill or incinerator for removal without energy recovery. Incineration creates bottom ash which ends up in the landfill and this landfill has to be carefully managed as it takes decades before full remediation of the land is reached.
Solid waste management is a small topic; I kept the article short and concise. Just remember the hierarchy pyramid and you are all set. The questions asked from this topic are more conceptual and hardly consume time. Let us have a question then ;-)