(Including Noarlunga Downs Sludge lagoon rehabilitation)
The Christies Beach Wastewater Treatment Plant (Plant) receives and treats wastewater (sewage) from the surrounding communities and industry.
Since the Plant was commissioned in the early 1970s the population of the region has increased and is expected to continue to grow over the next 25 years. To meet this expected population growth, SA Water is undertaking a $272 million upgrade to the Plant.
SA Water is working with Allwater to deliver the upgrade project and SA Water is responsible for the overall project delivery while Allwater, who currently operate the Plant, is responsible for the construction management of the upgrade.
The project will:
increase the capacity of the Plant to meet projected demand to the year 2030
reduce the nutrient load discharged to the marine environment
decommission and rehabilitate the Noarlunga Downs sludge lagoons
improve the general amenity of the area around the Plant.
Treatment Plant Upgrade works
In October 2008, the Development Assessment Commission approved the project, and construction started in 2009.
The upgrade of the plant has involved the construction of significant new infrastructure. Major construction works were completed in the first half of 2012 and some minor works will continue through 2012 and into 2013. The remaining work involves mechanical and electrical fit outs inside the structures that have already been built, as well as upgrades to elements of the existing plant that will remain part of the new treatment process.The following plant upgrade works have been carried out as part of the project:
An additional outfall pipe to carry the forecast future flows, which will provide superior dilution in the marine environment. The improved treatment process will greatly reduced the nutrient load discharged from the plant.
A new sludge management system has enabled the Noarlunga Downs sludge lagoons to be closed, with the sludge now being processed on site in a sealed building with odour and noise control measures in place.
A new blower building containing mechanical blowers that generate air used in the wastewater treatment process.
A new control and amenities building which is used by SA Water staff and our Allwater contractors who operate the plant.
A high voltage building that houses electrical switchgear that distributes electricity to various areas of the plant.
A new plant ('C' plant) that incorporates membrane treatment technology, which is some of the most efficient and effective technology available to remove bacteria and solids from treated wastewater.
An ultraviolet disinfection process (replacing a chlorine process) to disinfect the treated wastewater from 'C' plant and produce a better quality product prior to discharge.
An additional digester to augment the plant digestion capacity, which also allows the sludge methane gas produced by the process to be converted to electricity to supplement the power needs of the plant.
New inlet works at the very start of the treatment process to remove rags, plastics, grit and hair.
New electric security fencing to help protect plant equipment and prevent vandalism.
An upgraded dual cycle/pedestrian coastal path located along the top of the sand dunes in front of the plant.
Extensive landscaping has also been planted on and around the plant site.
Sludge lagoons rehabilitation
With the introduction of the new sludge handling facility at the Christies Beach Wastewater Treatment Plant, sludge lagoons at Noarlunga Downs associated with the previous treatment process have been decommissioned and remaining sludge from the previous treatment process has been removed.
After seeing views from the community and a number of environmental investigations, it was determined that the most suitable future use for the site would be stormwater wetlands. This new land use will:
- be compatible with the surrounding estuarine environment,
- extend the existing urban stormwater treatment entering the Onkaparinga River,
- provide important habitat, and
- improve amenity for the area.
The wetlands have been designed with both an aquatic (wet) zone and terrestrial (dry land) zone in order to provide important habitat for a variety of flora and fauna.
The aquatic zone has been designed using the existing lagoon structures. Embankments around the lagoons will be established, along with differing soil heights within the lagoons to create islands and different water depths that vary seasonally. This variation in water depths will assist in attracting and sustaining a variety of different bird species. Public access to the aquatic zone will be restricted to provide a haven for fauna and flora.
The terrestrial zone will be formed in a section of land previously used for yabby farming, adjacent the aquatic area to the east. The terrestrial area will include a walking trail, providing connection to existing pathways, and boulders for informal seating.
The entire wetland site will be landscaped with indigenous plants, both aquatic and terrestrial, grown from seed collected in the area.
Stormwater will enter the wetland from existing ponds managed by the Department for Environment, Water and Natural Resources. The water will then move progressively though each lagoon prior to entering the Onkaparinga River. This natural process will remove nutrients from the stormwater making it cleaner when it enters the River.
Earthworks started on 29 January 2013 and are expected to be completed in June 2013. Following this, landscaping will occur in stages over the next 19 months. Once construction is complete, SA Water will maintain the site to ensure successful establishment. This will include undertaking weed control, plant survival monitoring, plant replacement and water level control. This period will continue until 2015 and then the site will form part of SA Water's regular maintenance plan.
Or contact SA Water's customer call centre
1800 812 362
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