Groundwater Injection & Recovery (GIR) System - Proposed Backup for the Groundwater Treatment Plant

In planning for the ongoing treatment of contaminated groundwater at Botany, Orica needs to consider how treatment could continue in the unlikely event that the Groundwater Treatment Plant (GTP) could not operate for an extended period. This is important to ensure that contaminated groundwater is prevented from reaching Botany Bay.

While the Steam Stripping Unit at the Botany Industrial Park (BIP) was initially used to treat groundwater while the GTP was under construction and during the early stages of GTP commissioning, the plant can no longer be relied on as an alternative treatment facility. Orica examined other alternatives and selected Groundwater Injection and Recovery (GIR) system as the most viable and sustainable long term backup solution. 

Proposed Technique

The GIR system uses a technique called ‘aquifer storage and recovery', which allows water to be injected and stored in aquifers for later extraction and reuse. It is an increasingly common technique that can be used for storage of water that can be later recovered for beneficial use.

How the GIR System Would Work at Botany

GIR system will not act as a backup for the entire GTP capacity but will collect contaminated groundwater from critical locations to protect human health and the environment. The primary focus will be the Secondary Containment Area (SCA), located on Foreshore Road near Botany Bay (refer to figure below).

The extracted groundwater would then be piped to the BIP before it is reinjected into the aquifer upgradient of the BIP Containment Line. The reinjected groundwater would be recovered once the GTP is operational again. In effect, the contaminated groundwater would be temporarily stored in the aquifer. The quality of the injected water would be similar to or better than the quality of the groundwater in the injection zone.

Proposed location of GIR system (green line) in relation to

the containment areas (yellow lines) and the GTP

When Is GIR System Proposed To Be Used?

This system would only be used in the event that the GTP is shut down for an extended period. It would ensure that Orica could maintain hydraulic containment in essential areas while repairs are made to the GTP. Brief shutdowns do not compromise hydraulic containment.

Orica would continue to monitor the level of hydraulic containment that is being achieved in critical areas during any shutdown of the GTP and would regularly review and assess the need to commence operation of GIR system.

Orica has been sharing details on the GIR system proposal with the Community Liaison Committee (CLC) since 2007. The CLC sought advice on the proposal from independent hydrogeology expert, Professor Ian Acworth, a member of the Independent Monitoring Committee (IMC). To view Professor Acworth's comment on the proposal, click here.

Next Steps