Over four days, a team of around 25 Unitywater staff and contractors took a huge step to meet the sewerage needs of a growing population.

In a coordinated integration exercise, they redirected sewage from growth hot-spots Mountain Creek, Sippy Downs and southern parts of Maroochydore via a new $17.7 million Mountain Creek to Kawana pipeline into the Kawana Sewage Treatment Plant (STP).

Unitywater Executive Manager Sustainable Infrastructure Solutions Amanda Creevey said the mega-commissioning was a complex undertaking for many reasons.

“The keystone was completion of new treatment infrastructure at Kawana STP, which is part of a $74 million upgrade. It allowed many pieces of new and old infrastructure to be integrated, fulfilling our strategic plan for Kawana STP to service multiple surrounding high-growth areas, now and into the future,” Ms Creevey said.

Two upgraded sewage pumping stations, 132kW and 70kW, at Mountain Creek are vital contributions to the new sewerage network. Each boasts an innovative pressure vessel that protects the network from surges that strain the system and can result in bursts and sewage spills.

The Mountain Creek to Kawana sewer rising main is another major contribution. After completion last year and whilst awaiting commissioning, the 3.2 kilometre, 900mm pipeline was filled with 1.4ML of river water which deteriorated over time.

“If this volume of stale, silty water had been directed straight into the new Kawana STP, it would have overwhelmed the anaerobic digester, killing the bacteria that do the treatment work,” Ms Creevey said.

“However, the old STP could accept and treat the water, so some carefully timed diversions directed the pipe contents to the old STP, before the sewage following along in the pipe was redirected to the new STP.”

The Unitywater team collaboration cleverly brought the new sewerage network to life, making it ready to serve its surrounding communities for many years to come.