Project Round
Project Number
32M - 2046
Research Organisation
Knox City Council

Knox Leisure Works pool backwash recycling and re-use


The Challenge

Providing a safe playing surface for users of sportsgrounds has increasingly become an area of concern during drought, as grounds receive less rainfall and water restrictions prevent them from being irrigated as frequently.

While transitioning sportsgrounds to warm season grasses has been recognised as one solution, Knox City Council in Melbourne’s east also saw the potential to recycle water from other water intensive community facilities within close proximity of thirsty sportsgrounds for irrigation purposes.

Aquatic centres in particular, discard large volumes of water into the sewer through backwash processes and once treated, have the potential to provide an excellent source of non potable water that can be used to irrigate community facilities, as well as for other uses including toilet flushing.

To demonstrate the feasibility of using treated pool water to irrigate sportsgrounds, the project would have to determine an appropriate treatment system required to ensure water quality was not compromised.

The Project

Following a water audit at Knox Leisureworks in Boronia in Melbourne’s south east, swimming pool backwash water and roof run-off water were identified as significant sources of alternative water for open space irrigation at nearby Tormore Reserve, located approximately 250 metres away.

The first stage of the project involved a detailed study of the existing water quality and determining an appropriate treatment system required to minimise any adverse health or environmental impacts.

The second stage of the project included the design and construction of a re-use system.

The project now sees potable water used to ‘backwash’ filters at the Knox Leisureworks swimming pools treated and pumped to a 172,000 litre tank at the nearby Tormore Reserve. Through a process known as ‘reverse osmosis’, the water is treated to a quality comparable with drinking water before being used for irrigation.

The Outcome

The project is expected to save up to 18 megalitres of water a year and effectively drought-proof one of Knox’s top sporting grounds, providing a safe playing environment for the users by minimising the risk of injuries.

The economic benefits for the user groups (YMCA, Boronia Cricket and Football Clubs, Boronia Primary School) also include a reduction in water usage and sewage disposal charges.

Environmental benefits include a significant reduction in the use of high quality potable water for irrigating sports ovals and an improvement in the quality of water being discharged into the sewer.

Other flow-on benefits include the opportunity to highlight water conservation to the many groups that use Leisureworks and Tormore Reserve, as well as to other councils or community organisations.