The $A118 million ‘Three Towns’ sewerage scheme connects residents and businesses in Glossodia, Freemans Reach and Wilberforce with a reticulated sewerage system, northwest of Sydney. The project involves the construction of over 116 kilometres of pipeline with a large percentage undertaken by Horizontal Directional Drilling.
The scheme will provide improved sewerage services to the un-sewered urban areas of the three towns through the installation of a pressure sewerage system and associated infrastructure. Wastewater from the three towns will be transferred via a new pump station at Freemans reach directly to the Richmond Sewerage Treatment Plant (STP). By connecting to the new system residents will be helping to reduce the number of septic systems in the area. This will improve local waterways and reduce the risks to public health.
UEA was engaged primarily for two portions of the work on the Three Towns project. These included the design and construction of the 460m gravity storage pipe from the new Freemans Reach pump station and the installation of a 250mm transfer main under creeks and roads from the newly constructed pump station to the upgraded Richmond STP.
Works within the pump station site required a large excavation to allow the setting up of the D100 x 120 on a positive grade from the beginning of the bore. Difficulties arose when large Quartzite cobble was encountered along the bore line of the same type requiring casing on the Hawkesbury River HDD crossing. Forward thinking by the PSP delivery team and UEA staff developed a successful methodology whereby a shaft was excavated over the required connection point eliminating the need for casing and allowing the successful installation once reaming works were complete.
Installation of the 250mm transfer main included several creek crossings, two main road crossings, working in close proximity to defence force assets and the under boring of the Western Suburbs railway line whilst remaining in service.
For more information about this project or UEA Trenchless, please send enquiries to Steven Hopkins.