The Winmalee Sewage Treatment Plant (STP) was commissioned in the 1980s to meet the needs of a growing population in the Penrith area. In 2015, a Pollution Reduction Program was imposed that required Sydney Water to reduce the plant’s nutrient loads, necessitating the $60 million upgrade of the STP.

BG&E was the project’s principal structural engineering resource responsible for the delivery of the concept and detailed structural design for all structures on the project.

The scope included

• Inlet works.
• Membrane bioreactor tanks.
• Ancillary structures (including chemical storage, blower and switchrooms).

The project was an upgrade of an existing facility on a space-constrained site and required careful management of the civil and structural design as well as close coordination of the cross-discipline design to ensure there was no disturbance to ongoing operations during construction and commissioning.

Upon completion, the project addressed reliability constraints, increased capacity for servicing the current and projected population beyond 2030, and ensured the plant met new environmental protection licence requirements.