Recycling & re-use

Large irrigator spraying water on pasture land

Picton Farm uses recycled water to irrigate crops and pasture.

Our recycling program is diverse. It includes: 

  • recycling water at our treatment plants
  • treating wastewater solids to produce biosolids. This process creates heat and electricity that we re-use at our wastewater and water recycling plants
  • recycling other resources.

We're committed to protecting and maintaining the environment through renewable energy and efficiency initiatives, including reducing our carbon footprint.

We've been recycling water since the 1960s. We started with small irrigation projects and now produce billions of litres of recycled water each year.

We provide recycled water for:

  • heavy industry
  • golf courses
  • homes
  • a river system.

What’s recycled water?

Recycled water is really just water.
We take wastewater, that's been used in homes and businesses, and put it through a multi-step treatment process to remove impurities. The purified water can be used in many ways.

Recycling makes our water supply more secure and sustainable. 

How is recycled water produced?

Recycled water can be produced using:

  • water recycling plants
  • sewer mining
  • on-site systems
  • stormwater harvesting.

Learn more about producing recycling water.

How can recycled water be used?

Clear recycled water bubbling from bottom of square tank.

We produce clear, high quality water at our recycling plants.

We treat recycled water to a high standard, but it’s not for drinking.

Our clear, high quality recycled water is very safe to use. We meet strict recycled water quality guidelines at all times. 

Recycled water can be used: 

  • in homes and businesses 
  • in industry 
  • to irrigate parks, farms and playing fields
  • for river health.

Learn more about using recycled water.

Recycled water isn’t the only thing we produce at our treatment plants. 

We also produce biosolids - the nutrient rich by-product of the wastewater treatment processes.

Biosolids are a rich source of phosphorus and nitrogen and can be used in agriculture, land rehabilitation, horticultural processes and mining.

Each year, we produce around 180,000 wet tonnes of biosolids from Sydney's wastewater. The strictly regulated process allows 100% beneficial re-use in agriculture. This results in greater crop yield for Australian farmers and improved environmental outcomes.
We support the Australian and New Zealand Biosolids Partnership.

How do we know that biosolids are safe?

The NSW Environment Protection Agency (EPA) and NSW Health advise that biosolids are safe if produced and used in line with their guidelines. We meet all the requirements in the guidelines.

To learn more about the biosolids guidelines, visit NSW EPA and NSW Health.

How are biosolids produced?

When solids are separated from wastewater during the wastewater treatment process, they go through biological treatment. This reduces pathogens, odours and particles that attract insects and vermin.

All biosolids we produce are tested at laboratories to ensure they comply with regulations to protect human health and the environment.

Our $25 million biosolids program uses the latest technology and treatment processes. This ensures we can:

  • recover resources for a range of uses
  • continue to protect public health
  • reduce odours
  • reduce operational costs. 

Find out more about How biosolids are produced.

How can biosolids be used?

They can be used for many purposes.

Examples of biosolids use Benefits of biosolids
Agriculture Nutrients from biosolids are released slowly during plant growth. This increases crop production, provides superior water holding properties and replaces nutrients removed from soil by harvesting.
Composting Biosolids are mixed with other organic materials such as green waste, shredded timber and sawdust and allowed to compost naturally. This material is usually mixed into the soil to improve soil structure and help hold water.
Land rehabilitation Biosolids are used to restore mine sites and degraded agricultural land.

How can you help?

You can help us produce high quality biosolids by:

  • not putting paint, pesticides, medicines or other chemicals down the sink or toilet
  • using low phosphorous or phosphorous-free detergents and pesticides 
  • not pouring grease, oil or milk down the sink or toilet.


Lush grassy pasture

Biosolids help improve degraded agricultural land.

Person standing next to large pipes and valves.

We use cogeneration processes to produce electricity at North Head.

We're committed to protecting and maintaining the environment through renewable energy and efficiency initiatives.

Our Renewable Energy Generation Program is part of our pledge to reduce greenhouse gas emissions.

Our program includes producing electricity:

  • from wastewater gases at a number of our wastewater treatment and water recycling plants. This is called cogeneration
  • using treated wastewater and drinking water flows. This is called hydroelectricity.

Find out more about energy management and climate change.

Modern 2-storey office building and large silver rainwater tanks

We store and use rainwater at our Potts Hill office site.

We avoid generating waste wherever possible.

Our goal is to reduce waste through recycling and re-use and to encourage our suppliers to minimise waste.

Our waste procedure is consistent with the NSW Government's Waste Reduction and Purchasing Policy (WRAPP). We publish a yearly statement that outlines how we apply our waste reduction strategies. It includes details about:

  • reducing the amount of waste we generate
  • recovering resources by recycling and re-using them
  • using recycled materials. 
How much can we recycle?
We recycled and re-used 99% of all materials when we upgraded Warriewood Wastewater Treatment Plant.