Remediated Lands Management

Remediation - Blaxland Riverside Park
               Photo: Sydney Olympic Park

Sydney Olympic Park Authority has responsibility for the day-to-day and long-term management of 10 engineered landfills constructed between 1983 and 2001. These span some 105 hectares and have been rehabilitated and transformed into open space and parklands.

The Authority is committed to managing these remediated landfills and leachate systems to ensure:

  • their integrity is maintained
  • human health and the environment is protected
  • statutory compliance is achieved

Leachate (liquid waste) produced by the landfills must be contained and treated without risk to people or the environment. Leachate collected in subsurface collection drains gravitates to a pump pit where it is transferred under pressure to a treatment location. The leachate transfer system consists of over 12 kilometres of rising mains, 26 pump pits, 12 treatment ponds, and 3 storage tanks. The majority of leachate is treated at a nearby commercial liquid waste treatment facility. Some leachate is treated in constructed evaporation ponds. Leachate from the site of a former gas works facility at Wilson Park is treated in bioremediation ponds where bacteria degrade hydrocarbons to water and carbon dioxide.

Landfill management is regulated under the Contaminated Lands Management Act 1997, and a comprehensive environmental monitoring program is conducted to provide ongoing assessment of the effectiveness of the waste containment system.  

History

The remediation of past domestic, commercial and industrial waste sites at Sydney Olympic Park was the largest project of its kind in Australia and is one of the most significant environmental legacies of the Sydney 2000 Olympic and Paralympic Games

Controlled and uncontrolled landfilling operations occurred over several decades on lands that are now within Sydney Olympic Park. The majority of landfilling operations were broadacre fill, and few if any environmental controls were applied.

In a site-wide study conducted in 1991, boreholes were installed on a 50m grid across the site, generally to a depth of 1.6m. Soil and groundwater samples were collected for laboratory analysis to determine the locations and nature of wastes; further investigations were conducted where indicated. Approximately 160-hectares of the site was identified as containing wastes including power station ash, demolition rubble, asbestos, industrial hydrocarbons, domestic garbage, and dredging material from the Parramatta River

Between 1992 and 2000, the NSW Government allocated $137 million for remedial action to clean up polluted areas. The remediation policy at the time was to safely contain and where possible treat, waste on site, rather than relocating it to other places.

Many investigations were done prior to the commencement of works. Pollution profiles of various areas were established and groundwater and soil investigations undertaken, as well as studies of the natural environment.  

Remedial action varied according to the type and location of the waste and local hydrological and soil conditions, and included the recovery, consolidation and containment of about 9 million cubic metres of waste. Approximately 400 tonnes of soil contaminated with hydrocarbons and classified under environmental legislation as scheduled chemical waste was treated in a two-stage thermal desorption process. The majority of the buried waste was removed and relocated to designated waste containment mounds. These areas were capped, landscaped and turned into parkland. Leachate collection and transfer systems were built to prevent leachate from escaping into the environment.  

The remediation works were regulated by the Environment Protection Authority, and subject to stringent conditions directed at ensuring environmental protection and public safety. Following remediation, the landfills were certified as suitable for use as parks and recreational open space by an accredited site auditor, in accordance with regulatory requirements.