These guidelines apply to the injection of water or remediation chemicals undertaken for the remediation of groundwater in an aquifer.

In accordance with the Environment Protection Act 2017 (the Act), a 'waste' includes 'matter, including solid, liquid, gaseous or radioactive matter, that is deposited, discharged, emitted or disposed of into the environment in a manner that alters the environment'. Accordingly, the injection of water or remediation chemicals for the remediation of groundwater in an aquifer would involve the discharge or deposit of 'waste' that would otherwise require a permit pursuant to section 46 of the Act.  

The remediation of groundwater by way of injection of water or remedial chemicals may include:

• injection of any gaseous matter such as air, oxygen, carbon dioxide, steam, etc.
• injection of water or any water-borne chemical, for example nutrients to assist the growth of bacteria that degrade some contaminants
• injection of any liquid chemical, for example oxidation compound, reduction compound or other amendment
• injection of biological or bacterial mixtures
• extraction, treatment and re-injection of groundwater, for example pump and treat systems
• placement of any matter into a well or excavation, for example installing oxidation compound socks into a groundwater well, spreading of chemicals at the base of an excavation.

These guidelines do not affect the operation of other relevant laws with respect to groundwater.  It is important to note that even where a permit is not required under the Act, a licence under section 76 of the Water Act 1989 (the Water Act) may still be required for the 'underground disposal of matter via a bore'.  Further, bores constructed to inject or discharge chemicals may need to be licensed under section 67 of the Water Act, and any groundwater extracted may need to be licensed under section 51 of the Water Act.

Discharges or deposits of waste to an aquifer that are not for the purpose of remediation of groundwater will generally require a permit under the Act.  Exception may apply for discharges undertaken in accordance with a licence issued under the Act, or where otherwise undertaken in accordance with the Greenhouse Gas Geological Sequestration Act 2008.