Sewer mining

By recycling wastewater, we save our drinking water for drinking

Map of recycled water sewer
mining schemes in Sydney, the
Blue Mountains and the Illawarra.
Click to enlarge (PDF - 1055KB)

Sewer mining is the process of tapping into a sewer (either before or after the sewage treatment plant) and extracting sewage, which is then treated and used as recycled water. Some sewer mining by-products may be acceptable for return to the sewerage system.

Recycled water is treated so it’s safe to use. Recycled water produced from a sewer mining operation is commonly used to irrigate sports fields, parks and golf courses. It can also be used in some commercial buildings and industrial sites.

Sewer mining reduces the stress on waterways by capturing some of the nutrients that would otherwise be discharged from sewage treatment plants. The demand for drinking water can be significantly reduced, by replacing it with recycled water made available through sewer mining processes.

Sewer mining facilities

Sewer mining operations can be large or small. A sewer mining facility consists of:

• a connection to Sydney Water's sewer to extract wastewater
• a system to transport wastewater from the extraction point to the treatment site
• a wastewater treatment plant.

The operation may also include:

• a system for distributing recycled water
• a connection to Sydney Water's sewerage system to discharge approved residuals
• a system to manage any other by-products produced in the facility.

There are various types of treatment technologies available to treat wastewater obtained from sewer mining. Wastewater treatment will generate:

• recycled water suitable for a particular use
• grit and screenings
• other residuals, including a more concentrated version of the extracted sewage, which may contain treatment additives.

Before constructing a sewer mining facility, decisions need to be made about how the recycled water will be distributed and the remaining waste removed or discharged.

Sewer mining exclusion zones

Anyone can apply to Sydney Water for sewer mining approval. There are general requirements that outline what is needed for most sewer mining schemes.

Some areas of the sewerage system are closed to sewer mining. This may be because the sewage flows are committed to proposed water recycling schemes, or there are other sewer mining or recycling schemes already in place and there is no further sewage available for sewer mining.

Sewer mining schemes in Sydney

The NSW Government's Metropolitan Water Plan encourages the private sector to implement innovative solutions to secure Sydney's water supply, particularly by recycling.

• Sydney Olympic Park - The Sydney Olympic Park Authority's Water Reclamation and Management Scheme at Homebush Bay was Australia's first large scale urban recycling scheme to source wastewater through sewer mining for irrigation and residential non-drinking uses. Recycled water replaces 50% of the drinking water that would otherwise be used at Sydney Olympic Park and Newington Estate.
• Pennant Hills Golf Club - Pennant Hills Golf Club's Water Reclamation Plant produces up to 100 million litres of recycled water each year to irrigate the golf course. This sewer mining project was the first of its kind for a privately run golf club in Australia. Previously, the course relied on drinking water for irrigation.
• Kogarah Council - Kogarah Council became the first council in Sydney to pilot sewer mining. Up to 125 million litres of recycled water will be produced each year to irrigate parks, playing fields and the Beverley Park Golf Course.
• Workplace6 - Workplace6, located in Pyrmont opposite Star City Casino, is the first commercial development in NSW targeting a six-star Green Star energy rating. The on-site sewer mining facility is able to produce up to 14 million litres of recycled water each year for toilet flushing and irrigation of the site.

More schemes underway

Further sewer mining schemes are coming soon:

• Blackmores, Warriewood
• Ku-ring-gai Council
• Macquarie University, North Ryde
• North Ryde Golf Club
• Space, 1 Bligh Street Sydney
• Darling Walk, Darling Harbour
• Sydney Airport, Mascot
• Caltex and Koppers, Kurnell