Alice Springs Water Re-Use Project Update
All Power and Water Corporation (PWC) discharges and recharge under the Alice Springs Water Re-use Project are licensed, reported and monitored by the Controller of Water Resources and his/her delegate.
PWC received permission to extend its controlled overflows of treated effluent from the Waste Water Treatment Ponds based on the timeframe required to construct and commission the Water Re-Use plant. This was based on Power and Water's original estimate of the time required to complete the project.
This permission was granted by the regulator, the Environment Protection Authority (EPA) and in consultation with the Department of Health. As such, PWC has not breached its license conditions.
Power and Water has conducted pulse discharges into the swamp as required to reduce uncontrolled discharges. The pulse discharge arrangement means that effluent is discharged over a short time frame, thereby flushing through the swamp rather than moving slowly. This reduces the overall retention time of the water in the swamp and reduces the growth of reeds and mosquito breeding. The Ilparpa Swamp Rehabilitation Committee as well as the EPA and NT Health have agreed to the pulse discharges.
Power and Water completed its last anticipated pulse discharge in September (subject to any wet weather events) prior to the operation of the new reuse system.
The reuse pipeline to AZRI is slightly more than 6km long and the total cost of the project will be $10.4 million.
Power and Water and the Department of Natural Resources, Environment and the Arts (NRETA) are directly involved in the development and implementation of the scheme. The CSIRO was involved in the scientific work that developed
Alice Springs Water Re-Use Project Update 2 October 2007 the concept and provided specialist advice on recharge of the aquifer at the AZRI site.
The Environmental Protection Agency (EPA) and Department of Health and Community Services (DHCS) have a regulatory role and the Department of Primary Industries, Fisheries and Mines (DPIFM) is providing the land and negotiating with potential horticultural customers on the AZRI site.
The water reclamation plant is able to produce up to 6ML/day of treated water and the amount of land that can be irrigated with this water depends on the method of application adopted by the end user and the type of crops being grown.
All sewage will be treated in the existing series of Waste Stabilisation Ponds. Approximately 1000ML/yr is evaporated from the ponds that are earth lined. Treated effluent is withdrawn from the ponds and then further treated with chemicals to aid solids removal (predominantly algae) and to correct the pH of the water.
The algae are removed using a process known as Dissolved Air Flotation (DAF). The water is pressurised to several hundred kilopascals and saturated with air. When the pressure is released, bubbles form which adhere to the flocculated solids and allows them to be removed. The clarified water is then disinfected, and ready to be sent to AZRI via the reuse pipeline.
PWC’s Recharge Licence dictates the amount of water that can be sent down the pipeline to AZRI. This is currently fixed at 600ML/yr by the regulator. At the AZRI site, it is planned to develop 20ha/yr in 4ha operational blocks for a period of 5 years, resulting in a total area of 100ha. The negotiations with the horticultural user/s are being managed by DPIFM.
PWC is responsible for supplying any potential customers that access the water before it enters the aquifer. Existing users such as Blatherskite Park will continue to be supplied with water, but it will be with higher quality water from the new treatment plant, rather than directly from the ponds as is the current practice. Negotiations with new users are planned; however, Power and Water need to run the water reclamation plant for a period to demonstrate the effectiveness of the treatment process. Potential customers along the route of the pipeline will be contacted when the water quality has been confirmed.
Contact:
Judie Brennan
Media Manager,
Corporate Communications
Power and Water Corporation
0401 117 599 or 8985 8481
