Sustainability Report 2006/07Recycling east of Melbourne
A total of 21,136 million litres of recycled water was used at or near the Eastern Treatment Plant during 2007/08. This volume included 13,255 million litres that was used in operating the plant. If recycled water was not available, Melbourne Water would have had to use drinking water for these process operations.
The Eastern Treatment Plant currently produces Class C recycled water. The plant will be upgraded in 2012 to enable all sewage that enters the plant to be treated to Class A quality. Trials to determine the preferred technology for this tertiary treatment upgrade began during the year.
The upgrade will enable the plant to produce up to 135,000 million litres a year of high quality Class A recycled water suitable for use in new housing estates, irrigation and industry (see Sewerage, page 22).
Eastern Irrigation Scheme
The Eastern Treatment Plant has been instrumental in providing recycled water to customers on the Mornington Peninsula.
This has helped assess the extent to which recycled water can substitute for other water sources for irrigation, residential developments and industry in the area.
The proliferation of golf courses, council reserves and agricultural areas south-east of Melbourne presents a significant opportunity for recycled water schemes.
One such example is the Eastern Irrigation Scheme. Under this scheme, Melbourne Water delivers Class C recycled water from the Eastern Treatment Plant to a private sector operator, TopAq, which then carries out further treatment of the water using ultrafiltration membranes and chlorine to produce Class A recycled water ready for supply to customers.
TopAq delivers the Class A recycled water to a range of horticultural, recreational and residential customers via 50 kilometres of transfer and distribution pipelines. Melbourne Water supplied 6577 million litres of Class C water to TopAq compared with 8296 million litres in 2006/07.
The decline was due to reduced demand from TopAq customers.
This year, TopAq began installing additional membranes to increase the capacity of its Class A treatment plant. Commissioning is expected in early 2008/09.
Dual pipe schemes
TopAq supplies South East Water with Class A recycled water for its customers in the Sandhurst Club and the Hunt Club Estate.
These are the first residential estates in Victoria to have access to recycled water.
Class A recycled water supply via a dual pipe reticulation system was launched in December to about 600 houses in the Sandhurst Estate at Skye. Recycled water is used for toilet flushing, garden watering and open space irrigation.
South East Water also continued to supply Class A recycled water to about 200 houses at the Hunt Club Estate near Cranbourne.
A total of 123 million litres of recycled water originating from the Eastern Treatment Plant was supplied to these schemes via TopAq’s treatment plant.
Victorian Government legislation has mandated the supply of recycled water to all future residential developments in the Cranbourne and Pakenham growth corridors.
Pipeline customers
There are now 42 South East Water customers who take Class C recycled water from the South Eastern Outfall pipeline, which transports treated effluent from the Eastern Treatment Plant to Boags Rocks on the Mornington Peninsula.
These customers used 1304 million litres of recycled water for agricultural and horticultural activities, including watering golf courses and sports fields, for root crop irrigation, flower growing and drip irrigation of vineyards.
Three new South East Water customers, recycling an additional 80 million litres a year, were signed up in 2007/08.