The project site housed a gasworks from 1892 until 1958 which produced gas for the lighting of railway carriages and the Eveleigh Railway Workshops. The processing of coal and shale under heat and pressure to produce the gas created by-products such as tar and ash. These wastes were left on the site when the gasworks was demolished, which was common practice at the time. Over the decades however, the wastes have contaminated the site’s soil and groundwater. The contamination sources from the former gasworks infrastructure included the heating vessels known as retorts, tar and liquor tanks, coal stores, gasholders, boiler houses and purifiers.
Following an Environmental Assessment, RailCorp received approval in January 2013 from the NSW Department of Planning & Environment to remediate the site. The remediation was required under the Contaminated Land Management Act 1997, legislation administered by the NSW Environmental Protection Authority (EPA).
The Macdonaldtown Gasworks Remediation commenced in September 2014 and concluded in August 2016. It has improved the local environment by:
- Removing contamination caused by the former gasworks operation;
- Preserving the heritage values of the former gasworks; and
- Improving biodiversity via the revegetation of the western portion of the site with locally native species.
The main contaminants of concern at the site were polycyclic aromatic hydrocarbons (PAHs, including benzo(a)pyrene and naphthalene), total petroleum hydrocarbons (TPH), benzene, toluene, ethylbenzene and xylenes (BTEX) and small fragments of bonded, non-friable asbestos. Elevated concentrations of heavy metals had also been identified in groundwater.
A thorough pre-project assessment found that the risk to the community from contamination at the site was negligible. The contaminants at the site were however slowly leaching into groundwater and over time migrating towards the south-east (away from Burren St). The remediation will prevent this occurring in the future.
The remediation plan involved excavating the impacted material on the site to the extent practicable. The majority of the material was disposed of offsite to a licensed landfill. The most impacted, such as the tarry wastes, were treated offsite by cement stabilisation before landfill emplacement. Some lesser impacted material, which met specific criteria, was reinstated on the site at depth. When there were heritage or geotechnical constraints, impacted material was managed in-situ. This strategy was endorsed by a NSW EPA-Accredited Site Auditor.