The Waste Water Treatment plant on Hayden and McDonald contains parks and public areas around it. The building is done in a modern style with rusted metal, rocks in rusted mesh and blood red canvas sails for shade.

You wouldn't know it is a waste water treatment plant other than a back entrance has card access and a warning that only authorized personnel are allowed in. Immediately infront of the facility is a water feature and dog parks. There is a shaded amplitheatre of sorts behind the structure and then it blends into baseball parks.

It is possible that disguising it in the modern structure was a requirement or a means to fend of any NIMBY attacks so that it could go through council. It is quite a stunning building and well integrated into the surrounding public space.

Update: The maps.google satellite view is before the park was finished. The water treatment plant is done though.
Cam Riley: South Sea Republic. Freedom, liberty, equity and an Australian Republic.