Increase water recycling
As part of Water Forever: Lower Great Southern we have been looking for new ways to use our treated wastewater, especially for opportunities that replace the use of scheme water.
Albany Water Recycling
Water Corporation currently recycles 100% of treated wastewater from Albany’s Wastewater Treatment Plant (WWTP). This is used to irrigate 575 hectares of Tasmanian blue gums. Treated wastewater is pumped to the Albany Tree Farm then stored in a dam until required for irrigation.
The irrigation system consists of sand filters, chlorination and pH adjustment and drip lines to each tree. The trees are harvested and sold for wood chips, resulting in a small offset for running costs.
We are currently looking for opportunities to expand the tree farm to meet growth in Albany.
Walpole Water Recycling
We have recently completed long term planning for wastewater management in Walpole. The planning included identifying a range of options for treating and disposing of or recycling the wastewater, and then assessing the options against considerations, such as energy demand and cost. At Walpole, we are proceeding with upgrades to increase the capacity of the existing wastewater treatment plant. We are also developing a new tree farm to enable 100% reuse of recycled water through irrigation.
Denmark Water Recycling
We have also recently completed long term planning for wastewater management in Denmark. As with Walpole, the planning included identifying a range of options for treating and disposing of or recycling the wastewater and then assessing the options.
In Denmark, we identified that the best option is to construct a new, more energy-efficient wastewater treatment plant at the same location as the current one. Once the new plant is operating it will reduce significantly the nutrients discharged into the environment. Detailed design for the plant is under way and we expect it will be in full operation by 2012. The total cost of the new plant is expected to be around $8 million.
Planning for Denmark also considered the future potential for recycled water to be used at a number of sites, including:
• the golf course
• the Denmark Agricultural College
• new subdivisions
• a tree farm; and
• pasture irrigation
It is more viable to use recycled water during summer so we are continuing to work with our stakeholders to achieve this in the future.
Mount Barker – Recycled Water for Vineyard Irrigation
Mount Barker is another Lower Great Southern town where an innovative approach to reusing treated wastewater has resulted in 100% recycling. After treatment at the Mount Barker Wastewater Treatment Plant, the water is chlorinated then pumped to a storage dam at a nearby vineyard and irrigated onto the vines over summer. The nitrogen-rich water has allowed the vineyard to reduce its application of artificial fertiliser, providing economic and environmental benefits. This scheme has now been operating for 10 years and during this time the vineyard has continued to produce some of the fine wines for which the Great Southern has become famous.
A new recycling scheme may need to be developed as this vineyard has recently been sold. It is expected that the new recycling scheme will include irrigation of a timber plantation and/or irrigation of council parks and gardens.
Groundwater Replenishment
Water Corporation is investigating the potential for high quality recycled water to be returned to the environment through groundwater aquifers to be used for future drinking water supply.
Water Corporation is undertaking a three-year Groundwater Replenishment Trial (GWRT) in Perth to test the viability of this option and to fully understand any potential impacts on the environment or human health. If the trial is successful, and with regulatory approvals and community support, Water Corporation will develop a groundwater replenishment scheme for Perth.
Pending the outcome of this trial the opportunity may exist in Albany and Walpole, where suitable groundwater aquifers could exist, to consider groundwater replenishment as a future water source for these towns.