The pipelines provide water for the region’s power stations, industry and agriculture, as well as to the Wivenhoe Dam should the region’s drinking water supplies fall below a combined capacity of 40 per cent.

Water flowing through these pipelines marks completion of Stage 2A for the $2.5 billion Western Corridor Recycled Water Project – the largest in the Southern Hemisphere and the third largest in the world. The project now has the capacity to provide up to 182 megalitres (ML) of purified recycled water a day, and will be able to deliver up to 232 ML a day by early next year.

The project includes a network of more than 200 kilometres of large diameter underground pipelines, three advanced water treatment plants, storage tanks, and pumping stations. Sixteen of the world’s leading construction, engineering, project management and water services companies formed five alliances to construct the project, along the way employing thousands of specialists from more than 40 countries and clocking up almost seven million work hours. The project alliances involved significant collaboration between the Queensland Government and private companies, with common themes being a risk and reward sharing, no-fault and no-blame culture with unanimous decision making.

While recent rain has taken immediate pressure off dams, the project continues to play a key role in South East Queensland’s water supply strategy by creating a new source of pure water that is resilient to climate change and rainfall fluctuations. The project also provides significant environmental benefits by filtering water and removing solids that would otherwise be discharged into the environmentally sensitive Moreton Bay.

Project overview – the stages

Because of its size and complexity, the project was delivered in stages. Stage 1A – construction of the Bundamba Advanced Water Treatment Plant and associated pipelines – was designed to secure Swanbank Power Station’s water supply and take pressure off South East Queensland’s dams. Up to 20 ML of purified recycled water a day has been delivered to the power station since the achievement of ‘First Water’ just ten months after construction began.

Stage 1B involved delivery of additional water from Bundamba to Tarong Power Station and was completed in June 2008, just nine months after first water flowed to Swanbank. The Bundamba plant can now produce up to 66 ML of purified recycled water a day and has already delivered more than 10 billion litres of purified recycled water to the Swanbank and Tarong power stations.

Stage 2A entailed construction of the Luggage Point (66 ML a day capacity) and Gibson Island (50 ML a day capacity) advanced water treatment plants, and more than 80 kilometres of underground pipeline. A further upgrade of Gibson Island will double its capacity, bringing the project’s total capacity to 232 ML a day.

Western Corridor Recycled Water Pty Ltd CEO Keith Davies says “Plenty of pipeline innovations have been delivered and we’ve gained admiration and respect from engineering, industry and water bodies throughout Australia and the world.

“We’ve won nine highly sought after industry awards, including the 2008 ‘Water Project of the Year’ at the Global Water Awards and International Project of the Year from the Construction Management Association of America.”

Eastern Pipeline Alliance

The Alliance between AJ Lucas, Transfield Services and GHD on the Eastern Pipeline comprises 104 kilometres of underground pipelines, ten pumping stations and seven balance tanks. It involved around
50 crossings of roads, railways and major waterways, including the Brisbane River. Pipeline construction occurred through a heavily built up area and was complete in October, with Premier Anna Bligh signing the final pipe to be laid. At present, further drought contingency works are underway.

The first section comprises 58.5 kilometres pipeline from Luggage Point and Gibson Island Advanced Water Treatment Plants to a major pump station at Bundamba, where it links with the Western Pipeline. The second section is 17.1 kilometres long and transports treated wastewater from wastewater treatment plants in Oxley and Wacol to a triple pipeline section near Goodna. The third section is
9.7 kilometres of triple pipeline from Goodna to Bundamba, with a combined length of 29.1 kilometres. Three separate pipelines deliver purified recycled water, treated wastewater and reverse osmosis concentrate.

Mr Davies says one of the most innovative practices the Eastern Pipeline Alliance used was HDD.

“HDD was used to install up to 970 metres of pipeline underneath sensitive waterways, including the Brisbane River and Bulimba Creek,” he said.

“HDD was used to drill 700 metres from one side of Brisbane River to the other, passing 20 metres below the riverbed and steered to within 20 centimetres of its target on the other side.

“The alliance had to weld together about 700 metres of special 660 mm steel pipeline, before stringing it out on a continual length of rollers. The full length was then welded progressively, internally lined, externally coated and hydro tested prior to drilling.

“Following the hydro testing, the tunnel was bored out and the pipeline string was pulled back through the tunnel, using a bentonite lubricant, in a delicate five-hour operation.”

HDD delivered a number of benefits. It avoided the alternative of constructing 45 metre deep shafts at either side of the river and building large platforms to support construction and storage. It saved time and was environmentally sensitive, an important factor for the health of the Brisbane River and Moreton Bay. The result was a reduction in construction costs, enhanced workplace safety, reduced community impacts and improved environmental outcomes.

Western Pipeline Alliance

The Western Pipeline Alliance of McConnell Dowell, Abigroup and GHD constructed more than 80 kilometres of large diameter pipeline, two pumping stations at Bundamba and Lowood and two balance tanks at Esk and Lowood. Pipeline construction was completed in June 2008.

Starting at the Bundamba AWTP, the pipeline travels northwest for 32 kilometres to a 5 ML balance tank and pump station at Lowood. It then splits into two sections, with one heading 48.5 kilometres north to Caboonbah, via the Esk balance tank, where it links with pipelines supplying power stations at Tarong. The second section heads 16.4 kilometres to Coominya, where purified recycled water will be released into Wivenhoe Dam once combined dam levels fall below 40 per cent.

The Alliance was recognised for its speed of pipeline construction, with more than 50 per cent of the pipeline being built in just six months and, on one day,
1.52 kilometres of pipe was laid.

The pipelines

Three alliances were responsible for the advanced water treatment plants and two alliances – the Eastern Pipeline Alliance and Western Pipeline Alliance – were responsible for laying pipes and associated infrastructure. The pipeline starts at Luggage Point and Gibson Island Advanced Water Treatment Plants at the mouth of the Brisbane River, travels through Brisbane’s eastern and southern suburbs to the Bundamba Advanced Water Treatment Plant near Ipswich, then continues north to Caboonbah at the top of Wivenhoe Dam, where it taps into an existing pipeline to take water to Tarong storage lake. Construction began in late 2006.

The advanced water treatment plants

Three advanced water treatment plants located at Luggage Point, Gibson Island and Bundamba are central to the Western Corridor Recycled Water Project’s successful operation. The plants use a multi-barrier treatment process to produce purified recycled water that meets all water quality criteria contained in the Australian Drinking Water Guidelines and the Australian Guidelines for Water Recycling. Each of the water treatment plants will use similar technologies that have been successfully delivering purified recycled water in Singapore, Europe and the United States.

Key technologies used at advanced water treatment plants include microfiltration, reverse osmosis and advanced oxidation. In the microfiltration process, water is forced under pressure through filters with microscopic pores that remove suspended material and micro-organisms. In the reverse osmosis process, water is again forced through filters, but this time the pores are much smaller and remove viruses and inorganic compounds such as salt. Organic compounds, such as pharmaceuticals and pesticides, are reduced to extremely low levels that meet national standards. Advanced oxidation is the final step of the advanced water treatment process. It uses hydrogen peroxide and ultraviolet light to remove micro-organisms and destroy chemicals, producing a pure, safe and secure source of water.

Bundamba Alliance

Bundamba Alliance has completed construction of the Bundamba Advanced Water Treatment Plant, which produces up to 66 ML of purified recycled water a day to supply to Swanbank and Tarong Power Stations. The Thiess/Black and Veatch joint venture completed Stage 1A of the Bundamba Advanced Water Treatment Plant in August 2007, less than ten months after construction commenced. Despite work continuing for up to 24 hours a day, six days a week, excellent standards were maintained with
1.7 million workforce hours completed without a lost time injury.

Gibson Island Alliance

Gibson Island Alliance comprising of, MWH, Worley Parsons, Baulderstone Hornibrook and United Group Infrastructure is responsible for constructing the Gibson Island Advanced Water Treatment Plant, which produces up to 100 ML of purified recycled water a day. The Alliance is constructing the project’s largest plant on the smallest site.

More than 30 innovations were delivered during construction, with a number of these being implemented following suggestions from the construction workforce. These resulted in cost savings and productivity improvements. In keeping with the project’s water sustainability precepts, environmental engineers devised a means of capturing and recycling rain water from the roof of the main process building and redirecting it to the water treatment plant.

Luggage Point Alliance

Luggage Point Alliance of CH2M Hill, Laing O’Rourke, Connell Wagner and Hatch constructed the Luggage Point Alliance Advanced Water Treatment Plant, which produces up to 66 ML of purified recycled water per day. Luggage Point built a scaled down pilot plant to simulate a full-scale advanced water treatment plant.

Different membrane technologies were tested to ensure they were suited to Australian conditions. The pilot plant also allowed tests on the quality and consistency of the purified recycled water produced. Pilot wetlands were also trialled for effectiveness, but land prohibitions made this option unfeasible.

Water delivery

Now that the construction phase is almost complete, change is occurring within the Western Corridor Recycled Water Project. Moving forward, Western Corridor Recycled Water Pty Ltd has been brought together with SureSmart Water (the Gold Coast desalination plant) to create WaterSecure. The Gold Coast Desalination Plant began delivering water to the South East Queensland Water Grid at 100 per cent capacity on the
9 March this year. The plant will shut down in late April for a number of weeks so that identified defects can be repaired.

Mr Davies, who has now become WaterSecure CEO says that the new entity combines the fundamental benefits of recycled water and desalination, allowing for sustained population growth demands being placed on the region’s resources.

“If you do what you’ve always done, you’ll get what you’ve always gotten. And we really don’t want to be in the same water supply situation we found ourselves in 18 months ago,” he said.

“We’ve combined two climate independent water sources to produce a pure source of water that will directly assist population growth, economic growth and water supply certainty. And we’re very proud of our efforts.”