Wastewater treatment

Managing up to 130 million litres of wastewater

Our Waste Assets Management Corporation manages and treats up to 130 million litres of wastewater a year across various closed landfill sites. This is equal to about 50 Olympic-sized swimming pools of wastewater.

Each site has a dedicated 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. Leachate is liquid that carries contaminants.

We manage wastewater levels within the landfill to improve biogas production and to comply with the terms of our site licence from the NSW Environment Protection Authority. Managing the wastewater levels also reduces greenhouse gas emissions.

We have installed wastewater treatment systems 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).

Benefits

Onsite management of waste water reduces costs for the Waste Assets Management Corporation and reduces the reliance on offsite treatment systems. It allows us to effectively control the wastewater volumes across various landfill sites, complying with the conditions of the licence from the NSW Environment Protection Authority.

The Waste Assets Management Corporation uses solar energy generated from the roof of the wastewater treatment plant to cut its reliance on the electricity network and to minimise its carbon footprint.

Next steps

The Waste Assets Management Corporation will continue to operate the wastewater treatment systems to ensure liquid levels within the landfill cells remain low and comply with licence requirements.  

We are likely to operate and maintain these systems for the next 20 to 30 years.

Background

The Waste Assets Management Corporation manages 9 closed landfill sites across NSW, rehabilitating landfill 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
• the landfill assets, including gas, which is regulated by the NSW Environment Protection Authority
• leachate and groundwater monitoring and security systems
• the assets, plant and equipment.

When liquid from rainfall, groundwater or the biological breakdown of waste itself passes through waste material, it generates wastewater and becomes contaminated.

The wastewater is contaminated with organics, ammonia, heavy metals and suspended solids that we must treat before releasing the wastewater into the environment.

A series of plastic pipes collects the wastewater. A pump then transfers it to holding dams for storage before treatment and disposal. An aerobic treatment process uses microbes and oxygen to degrade the contaminants before discharging the water into the sewer system.

Site management

The wastewater is typically managed for 30 to 40 years after each landfill is closed. This ensures there are no negative effects on the environment.

Ammonia treatment

The Waste Assets Management Corporation manages and treats approximately 100,000 kg of ammonia yearly.

High ammonia levels in natural water systems such as rivers and creeks may harm aquatic life and can be toxic to freshwater organisms.

Key stakeholders

Our stakeholders include:

• NSW Environment Protection Authority
• Sydney Water
• other waste management service providers (Cleanaway, Veolia, GRL)
• the community.