About the project
Property and Development NSW’s (PDNSW’s) Waste Assets Management Corporation (WAMC) manages and treats up to 130 million litres of wastewater a year, the equivalent volume to about 50 Olympic-sized swimming pools, across various closed landfill sites.
Each site has a dedicated wastewater treatment plant to treat the raw wastewater from the landfill before it is discharged into the sewer system.
These engineered “cells” collect, contain and treat wastewater. The cells are lined, either with clay or a synthetic product, to prevent leachate entering groundwater, soil, creeks and rivers.
Wastewater levels within the landfill are managed to enhance biogas production and to comply with NSW Environment Protection Authority (EPA) site licence requirements, while also reducing greenhouse gas emissions.
Wastewater treatment systems are installed at the following sites:
- Eastern Creek closed landfill
- Thornleigh and Merrylands closed landfills
- Pasminco closed landfill
- Belrose (Bare Creek) closed landfill
- St Peters Interchange, Westconnex (managed on behalf of Transport for NSW).
WAMC is responsible for the ongoing management of nine closed landfill sites across NSW, focusing on landfill rehabilitation to minimise potential health and environmental risks.
Activities across the sites include monitoring, management and maintenance of:
- leachate extraction systems and leachate treatment and disposal facilities
- landfill gas capture and power generation or flaring systems
- EPA-regulated maintenance and monitoring of the landfill assets, including gas
- leachate and groundwater monitoring and security systems
- ongoing maintenance and operation of the assets, plant and equipment.
Wastewater is generated when liquid from rainfall, groundwater or the biological breakdown of waste itself, passes through waste material and becomes contaminated.
The wastewater is contaminated with organics, ammonia, heavy metals and suspended solids that require treatment before being released into the environment.
The wastewater is collected by a series of plastic pipes and transferred by pump to holding dams for storage prior to treatment and disposal. An aerobic treatment process uses microbes and oxygen to degrade the contaminants prior to discharge into the sewer system.
WAMC will continue to operate the wastewater treatment systems to ensure liquid levels within the landfill cells remain low and comply with EPA licence requirements. These systems are likely to be operated and maintained for the next 20 to 30 years.