Water management for regional community

An integrated water project servicing the towns of Agnes Water and Seventeen Seventy in Queensland has been designed for growth across the region without causing environmental damage to the pristine environment. TRILITY was contracted by the Gladstone Regional Council to provide the new infrastructure, including a wastewater treatment facility and seawater desalination plant.

Agnes Water and Seventeen Seventy are towns located at the southern end of the Great Barrier Reef in Queensland. Much of the surrounding area is home to pristine land and marine habitat including Deepwater National Park and nearby conservation parks. The entire township is heritage listed, and as such, any new infrastructure requires particular environmental sensitivity and care.

The Gladstone Regional Council required an alternative water supply and improved wastewater treatment capacity for the towns. Gladstone Regional Council said water supplies for the area had traditionally been sourced from the area’s limited groundwater resources. “Without additional water and improved use of all existing water resources, council had real concerns that supplies would be exhausted and the surrounding environment irreversibly harmed,” council said.

A number of solutions were investigated and it was decided that constructing a desalination plant installing a reticulation system and building a new wastewater treatment plant offered the best whole-of-life cost solution with minimal impacts on the community and environment. The council entered a 10-year, $40 million design, construct and operate contract with TRILITY.

The desalination plant has a capacity of 1.5 ML/day with the potential of being upgraded to 7.5 ML/day. This is augmented by the multimedia filtration plant which is able to produce 0.5 ML/day. The wastewater treatment plant has a capacity of 0.6 ML/day and discharges effluent to an irrigation system.

It was critical that TRILITY work with relevant authorities to consider the plant’s footprint, visual amenities, performance requirements, monitoring requirements, noise and energy use.

The focus on protecting the marine habitat intensified with the introduction of a horizontal directional drilling program that ultimately enabled the installation of a 600 m section of ocean intake and outfall pipelines. This work required the use of a 1.1 million pound horizontal directional drill and TRILITY had a small window of opportunity to finalise the program in order to work around turtle season.

The program involved sourcing specialised equipment from the US and the deployment of divers and local barges to install the pipeline on time and within specification. 

Another critical step in the project was establishing a community engagement capability, with a comprehensive community consultation program created to ensure all community stakeholders were aware of the project and that ongoing dialogue would ensure any future impacts were mitigated or minimised during construction.

The project’s engineers designed the plant to meet stringent noise level, energy-efficiency and environmental requirements. Construction was strictly monitored by the Queensland Department of Environment and Resource Management.

All Seventeen Seventy properties have now been provided with a connection to the new water supply while self-sufficient properties have a water connection for immediate or future use.

Seventeen Seventy property owners are now being connected to the council’s reticulated sewerage system. This eliminates the need for disposal trenches on private properties while providing a safe and environmentally sustainable sewerage solution for residents.

“Residents are seeing immediate benefits from the project following the design and construction of the Seventeen Seventy water reticulation pipelines and the Seventeen Seventy sewer system,” said TRILITY Managing Director Francois Gouws.

“While the wastewater treatment plant is not yet complete, the benefits are literally already flowing.”

Gouws said TRILITY thrived on the opportunity to develop the project in line with stakeholder expectations and the council and community’s requirements.