Waste immobilisation

Waste classified as ‘hazardous’ in accordance with the Waste Classification Guidelines due to high levels of contaminant(s) is generally not suitable for disposal to landfill in NSW. However, if the contaminants are ‘immobilised’ so that they will not be released into the landfill leachate at levels of concern, then the EPA may grant an immobilisation approval to enable the waste to be landfilled. Immobilisation approvals will only be issued where it is not possible to reuse, recycle or reprocess the waste. Where feasible, treatment to remove or destroy the contaminants is preferable to immobilisation.

The types of immobilisation are

  • Natural immobilisation, where the contaminant(s) are already present in an immobilised form and the waste is suitable for landfilling without additional treatment
  • Chemical fixation where the contaminant(s) are chemically converted to a stable form.
  • Microencapsulation, where the waste is treated to physically lock up the contaminant(s) in the structure of the treated waste
  • Macroencapsulation, where a physical barrier is placed between the contaminated waste and the surrounding landfill environment.

The science and technology of waste immobilisation is evolving rapidly. The EPA prepares technical notes based on technology reviews undertaken by the EPA. Applicants for specific immobilisation approvals should take relevant technical notes into account when preparing their applications.

Where the EPA has assessed wastes as either being naturally immobilised or able to be immobilised using well established techniques, it issues general immobilisation approvals for these wastes. General immobilisation approvals include conditions which must be met for the waste to be classified as suitable for landfill disposal. An application is not required to dispose of waste under a general immobilisation approval. However, some approvals require the person disposing of the waste to advise the EPA of their intention to do so.

Where no general immobilisation approval exists, The EPA may issue a specific immobilisation approval. Specific immobilisation approvals may be issued to enable the waste to be classified for both disposal and other purposes. The person intending to dispose of the waste must apply to the EPA for a specific immobilisation approval.

The EPA issues immobilisation approvals in accordance with Part 10 of the Protection of the Environment Operations (Waste) Regulation 2014.


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