Waste Streams

Classifying waste: material or source?

Our society uses, consumes and discards a diverse range of materials and does so in the course of a wide range of activities.  To assist with managing waste, many people find it useful to categorise waste according to either the characteristics of the material or the source of the material.  Thinking of waste in 'streams' is a habit of waste managers, but they aren't always explicit about whether they're thinking of a class of materials or a class of waste generators.  In addition, the term waste stream is sometimes used to describe a physical supply of waste whereas in other cases, the term refers to specific components mixed into that waste supply.  In practice, the waste streams cited in the side bar under this section often imply both material characteristics and waste sources. 

Click on the side navigation bar for more information on specific waste streams

Classes of sources

For waste managers within Local Government and for the purposes of strategic waste policy, grouping wastes into streams according to their source, often makes most sense.  This is generally true where waste is received in a highly heterogeneous form.  Municipal Solid Waste (MSW) is classic example of an aggregation of many different types of wastes within a single waste stream.  This waste stream was historically treated as a special kind of waste precisely because it came from households.  The source of MSW is particularly significant because state Health Acts require the removal of household refuse because the putrescible component in that refuse can attract vermin and disease.  The maintenance of public health remains the primary rationale for the management of MSW.  This is despite the fact that the putrescible component of MSW is a minor part of this waste stream and the physical characteristics of other components are quite different. 

Some of the common waste classifications based on the source of the waste include:

• Municipal Solid Waste (MSW)
• Commercial and Office Waste
• Construction and Demolition Waste
• Industrial and Mining Waste

Classes of Materials

The properties of waste which make them benign or hazardous, stable or unstable, recyclable or compostable, easy to deal with or problematic are often a helpful basis on which to categorise wastes.  This is because the ideal processing options are different for materials with different types of properties.  An emphasis upon classifying waste according to material type often makes good sense within the industrial sector, because wastes generated by industrial processes are often quite homogeneous and large enough to have specific treatments developed for them. 

For wastes commonly found outside industry, some common waste classifications based on material characteristics include:

• putrescible or non-putrescible
• organic or inorganic
• recyclable or non-recyclable
• hazardous
• problematic