Remediation of the Parramatta River and Foreshore

WICKED PROBLEM 1: REMEDIATION OF THE PARRAMATTA RIVER & FORESHORE

Industrial Waste Dumping in the 1950s and 60s

from the late 19th to mid 20th century, industrial activity spread along the southern foreshore of the Parramatta River and the river was commonly used to dispose industrial waste.

In the 1950s and 60s, industrial activity on the site had mostly ceased and the Sydney Olympic Park site was used to dump household and industrial waste. Most low-lying and mangrove areas were filled in with landfill, to the point where Wentworth Bay no longer existed by 1970.8

By 1988 it is estimated that the Sydney Olympic Park site contained 9 million cubic metres of waste which included “petroleum waste, unexploded ordnance, potential acid sulfate soils... dredged sediments, municipal waste, industrial waste including aesbestos.”9

Industrial activity has left high concentrations of legacy chemicals in river sediments, while leachate from contaminated foreshore land also contributed to toxic water conditions.10

Contemporary Sources of Contamination

Stormwater runoff is believed to be the greatest source of contaminants in the Parramatta River today. This is supported by evidence of higher concentrations of heavy metals in the river near major stormwater outlets. Urban stormwater carries high concentrations of human pathogens from municipal sewerage and is dangerous to human health.11

Stormwater modelling by Birch & Rochford in 2009 reported that 215 GL of stormwater is discharged to Sydney harbour via the Parramatta River per annum.12

Consequences of Water Contamination

• Presence of heavy metals and other toxic industrial substances in the Parramatta river are toxic to humans, animals & plant life. • Influx of pathogens and nutrients from stormwater runoff can promote the growth of certain algaes and other non-indigenous species that threaten ecocystems • Contact with water-bourne pathogens can cause illness in recreational users of the river.13 1990s Sydney Olympic Park Remediation Project

In 1991 a study was conducted to test water and soil conditions at Sydney Olympic Park via boreholes at 50m intervals. 160ha of the site were found to be contaminated. The NSW Government allocated $137million to remediate the site between 1992 and 2000 to prepare for the Sydney Olympics. The primary strategy was to contain & treat waste on site rather than relocating it. Remediation was overseen by the Environment Protection Authority.

Remedial action included:

• Hydrocarbon-contaminated soil was treated in a two-stage thermal desorption process (Indirect Thermal Desorption & Base Catalysed

Destruction). • Buried waste was relocated to wastecontainment mounds that included leachate collection and transfer systems.

By the end of the process, 37,000kg of contaminated material was remediated from 900,000 parts per million to less than 1 part per million.14

A clay-capped waste containment mount at Sydney Olympic Park. Image source: Centre for Creative Land Recycling

Ongoing Remediation Efforts

Sydney Olympic Park Authority is responsible for the long-term management of the engineered landfill sites that span 105 ha in the park.

Ongoing treatment of leachate from landfill sites is required. This involves 12km of mains, 26 pump pits and 12 treatment ponds. Leachate is collected in subsurface collection drains and taken via gravity to a pump pit which pumps it to a location for treatment.

The majority of leachate is treated at a nearby commercial liquid treatment plant.

Some leachate is treated in evaporation ponds or bioremediation ponds where bacteria converts hydrocarbons to carbon dioxide and water.

In 2014, a wetland system was introduced to treat the Blaxland Common landfill leachate as an alternative to offsite processing.15

SITE ANALYSIS:

REMEDIATION MEASURES IN SYDNEY OLYMPIC PARK

1:20,000

BLAXLAND COMMON LANDFILL One of the bioremediation ponds located in Wilson Park. Source: www.sydneyolympicpark.com

WOO-LA-RA LANDFILL

WILSON PARK BIOREMEDIATION PONDS

HASLAMS NORTH LANDFILL

KRONOS HILL LANDFILL ARCHERY PARK LANDFILL

WENTWORTH COMMON LANDFILL

LEGEND

LANDFILL ZONE

CLAY CAPPED WASTE MOUND

LEACHATE DRAIN

LEACHATE PUMPING LINE BICENTENNIAL PARK LANDFILL

GOLF DRIVING RANGE LANDFILL