Coolum STP

Project Summary

Unity Water sought to take advantage of perfect climatic conditions and explore the possibility of using nature to help treat the rapidly growing regions sewerage. This was not an easy task given the existing plant age of over 20 years with numerous extensions, and it could not be taken offline for any component of the works! 

The level difficulty and boldness of the idea presented a challenge that attracted Donnan Q to the tender. Using its extensive expertise, Donnan Q identified the critical connection that enabled the new installation of the wetland that would result in minimal impact to the plant’s operations. While Unity Waters initial design called up a serpentine design, Donnan Q instead offered two separate cells,giving a liner flow, which also provided increased efficiencies, greater redundancy and a large increase in the experimental testing that was possible. 

Using a specialist wetland consultant, Donnan Q offered further refinements, including the use of igots as the inlets to allow for easily adjustable flows and provide even flow across the wetland. A Schnider PLC was added for simplicity of operation, as well as multiple flowmeters centralized at the PLC for easy reference. Modern Sulzer pumps were provided for their reliability and variable speed characteristics.

Project Details


Unity Water

Project Value

$ 1.3 m

Project Duration

JUNE 2012 - current


Mt Coolum, Qld

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