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 of the following sites has a dedicated plant to treat the raw wastewater:

• 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 raw wastewater reduces costs for the Waste Assets Management Corporation and reduces the reliance on offsite treatment.

It allows us to effectively control the wastewater volumes across various landfill sites, prevents it from entering groundwater, soil, creeks and rivers, and reduces greenhouse gas emissions.

It also enables us to discharge the treated wastewater into the sewer system, in compliance with the conditions of our regulatory 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 treat the raw wastewater at each site to ensure liquid levels within the landfills remain low and comply with licence requirements.  

We are likely to operate and maintain our wastewater treatment plants 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.

When liquid from rainfall, groundwater or the biological breakdown of waste itself passes through waste material, contained within a landfill, it generates wastewater.

This raw wastewater is contaminated with organics, ammonia, heavy metals and suspended solids that must be treated.

A series of plastic pipes collects the raw 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 wastewater 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

We manage and treat approximately 100,000 kg of ammonia in raw wastewater yearly. The treated wastewater is then discharged to the Sydney Water sewer system under a Trade Waste Agreement.

High ammonia levels in natural water systems such as rivers and creeks may harm acquatic 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.