Googong Water Treatment Plant
The Googong Water Treatment Plant (WTP) was built in 1974 at the same time as Googong dam.
The Queanbeyan River catchment, which feeds Googong dam, is an occupied rural catchment, and extensive treatment is necessary to ensure a safe water supply. Recreational activities on Googong dam are controlled to avoid excessive turbidity (cloudiness) and contamination problems.
At Googong dam, water is drawn from the storage and pumped to the adjoining water treatment plant. Treated water is then fed to Canberra's service reservoirs through the Googong bulk supply main. Water from Googong supply is distributed to consumers in Queanbeyan, north and south Canberra, and the Woden/Weston Creek area during the summer months when water consumption is high. In the low consumption winter months, water from the Cotter system is used and the Googong system is shut down.
The Googong catchment supplied all of Canberra and Queanbeyan’s water in the immediate aftermath of the January 2003 bushfires, when the water quality from the Cotter catchment was poor.
The Googong WTP has recently been augmented to enable it to meet the average daily summer demand of Canberra and Queanbeyan. This ensures that high quality treated water can be provided should the raw water quality in either the Cotter or the Googong catchment deteriorates.
The augmented Googong WTP was commissioned in December 2004. A parallel treatment process was added to the existing conventional treatment stream. The new dissolved air flotation and filtration process can be run in addition to or instead of the original clarification and filtration system. The augmentation has increased the capacity of the plant from 180 megalitres (million litres) a day up to 270 megalitres a day.
The treatment of the Googong reservoir water involves conventional treatment such as:
- optional powdered activated carbon for organic matter removal, if required
- coagulation and flocculation
- dissolved air flotation and filtration (augmented plant) or clarification and filtration, depending on operation mode
- disinfection by chlorination
- pH adjustment and stabilisation with lime
- fluoridation by sodium silico fluoride.