Waste Water Reuse

• Why reuse wastewater in urban development?
• Selecting the appropriate wastewater treatment technology
• What technologies are available in Australia?
  
• Click here to download the full technical report: 'Wastewater reuse in the Urban Environment: selection of technologies' (PDF)

Why reuse wastewater in urban development? 
Sydney residents use more than 1.4 billion litres of drinking water every day. Much of this good quality water is used for activities that don't need a high standard of water quality (eg. flushing toilets). This clearly is not a sustainable way of life.

Sustainable water management is one of the key elements of sustainable urban development. Wastewater reuse is one of the options that must be considered in the broader context of a Water Sensitive Urban Design (WSUD) Strategy. Treating wastewater for reuse may be appropriate for a particular site after considering all other water streams and their interactions.

The conventional urban water cycle consists of a large-scale centralised water supply and disposal system. Water is collected from catchments, treated and piped to customers. After use, wastewater flows through sewers to sewage treatment plants where it is treated and then discharged to creeks, rivers, bays or oceans.

Sustainable development aims to minimise water use and maximise reuse within the built environment. This can be achieved by :

• reducing drinking water use through demand management
• using water quality that is `fit-for-purpose'
• identifying and maximising alternative water sources
• protecting our waterways

ABOVE: The dotted red line separates the natural and built environments. The general approach is to minimise water and pollutants crossing the boundary, and maximising wastewater reuse within the boundary.

Drinking water is currently the primary water source for most urban developments. Potential alternative water sources include rainwater and stormwater runoff, greywater and blackwater. For urban developments, reused water is suitable for toilet flushing, public open space irrigation, private garden irrigation/outdoor use, cold washing machine tap, environmental flows and ornamental water bodies.

Some of these uses and applications are subject to guidelines set by NSW Health, NSW Department of Environment and Conservation (DEC) and Department of Energy Utilities and Sustainability (DEUS).

Selecting the appropriate wastewater treatment technology  
The following 7-step decision-making process can help assess and compare the suitability of wastewater reuse technologies for a specific site.  For more details on the technical selection process see the full report.

What technologies are available in Australia? 
Increasing demand on water resources and the prolonged drought have combined to drive the market for wastewater reuse. Numerous commercially viable wastewater treatment technologies are available in Australia and the market for decentralised and localised wastewater treatment systems is continuously developing.

With the help of a number of wastewater technology suppliers we have compiled a list of technologies and suppliers available in Australia in 2005.

• Click here to view the complete list (PDF)
• Click here to download the full technical report: 'Wastewater reuse in the Urban Environment: selection of technologies' (PDF)