Inspire : Public Works Mar Apr 2014
CASE STUDY Sydney's Northern Suburbs Ocean Outfall Sewer (NSOOS) system was the third major sewerage system built to ser vice the metropolitan's growing wastewater needs. It consists of two major inverted syphons -- one of which, the Middle Harbour 'Spit' Syphon, is considered the best example of an inverted syphon, at its scale, in New South Wales. Constructed between 1922 and 1925, the Syphon crosses Middle Harbour in Sydney's north at The Spit, between Parriwi Point and Clontarf Flat, forming a vital part of the system servicing communities in an area covering more than 400 square kilometres. The historically signiﬁcant asset consists of two large concrete towers built in the 1920s with Art Deco and Egyptian architectural inﬂuence. In constant use since completion almost 90 years ago, the Syphon recently under went renovations as part of Sydney Water's SewerFix program, which aims to improve the wastewater system and protect public health and the environment. Pieter Schoofs, who managed the project on behalf of contractor Water Infrastructure Group, says that careful planning was required to minimise project risks in this high-proﬁle location. "Water Infrastr ucture Group designed a ventilation and odour-control system to provide a safe working environment and prevent any odour issues for nearby residents," Schoofs explains. "We also designed a walking bridge and working platforms so that our team could complete the work safely inside the syphon building." To minimise the impact on residents, the work was managed so that the syphon could continue its normal operation during the upgrades. "We car ried out concrete repairs and installed new stainless-steel covers to replace cor roded metal access lids," says Schoofs. "These works have extended the life of this important asset, eliminated the release of odour and provided improved and safer access for ongoing maintenance and operations. Water Infrastr ucture Group worked closely with Sydney Water to address issues that could impact on the local and wider Mosman community, particularly regarding the potential for release of odours. "We ensured that the works were completed prior to the Christmas break, and it was very pleasing to see that the effort we put into designing and planning an efﬁcient odour-control system was rewarded with zero community complaints,” Schoofs says. ••• SPIT AND POLISH The historically signiﬁcant ‘Spit’ Syphon in Sydney's north undergoes vital repairs. 33 Our planning e orts were rewarded with zero community complaints.
Public Works Jan Feb 2014
Public Works May Jun 2014