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North Head Process and Reliability/Renewals (PARR) Alliance

Improving treatment plant efficiency and the quality of Sydney's wastewater

Sydney Water Corporation
Contract Value
$92M AUD
Project Duration
Commenced: 2007
Estimated Completion
North Head, Manly, New South Wales
Project Overview

In August 2007, Sydney Water formed the Process and Reliability/Renewals (PARR) Alliance to complete a $92 million capital works program to renew and refurbish the North Head Sewage Treatment Plant. The plant serves a population of over one million people and treats approximately 300 million litres of flow a day, equivalent to 120 Olympic swimming pools of wastewater. The treated wastewater is then discharged via a 3.7km deep-water ocean outfall located off Sydney’s northern beaches. The PARR Alliance consisted of Sydney Water, UGL, John Holland, MWH, WorleyParsons and Manidis Roberts.


The Challenge

The discharges from Sydney Water’s treatment plants must comply with licences issued by the NSW Office of Environment and Heritage. These licences specify the quantity and quality of treated wastewater that can be released to rivers and the ocean.

To minimise the impact of treated wastewater discharged to waterways, Sydney Water recognised the need to upgrade its treatment processes.

The Solution

The upgrade works on the North Head Sewage Treatment Plant draw on UGL’s extensive experience in delivering unique wastewater engineering infrastructure solutions in Australia and overseas.

The upgrade works will substantially extend the life of the existing treatment plant, increase treatment flow performance while reducing operational costs to support higher standards of wastewater purification.

UGL’s role included the oversight of project management, design development, construction works, control system installation, commissioning services and operator training.

The scope of works comprised:

  • New underground screenings handling system
  • Grit removal system improvements including additional grit tanks
  • Primary sedimentation system improvements including additional tanks
  • Testing and commissioning of SCADA & Automation (Siemens technology) systems programs
  • Modifications to the Northside Storage Tunnel (NST) dewatering pump systems
Key Outcomes and Benefits

UGL’s step-by-step collaborative approach to the project gave the Alliance certainty in achieving the necessary outcomes. This approach also ensured that the challenge of working with multiple stakeholders would be successfully managed to deliver an optimal outcome.

Key successes included:

  • General reliability improvements to stormwater drainage systems, service air compressors, recycled water/filtered effluent supply, domestic water supply, ventilation filtration, structures and buildings corrosion remedial works and removal of redundant equipment
  • Elimination of the need to construct a new switchroom in the screenings area by relocating starters into existing switchrooms which resulted in lower civil work costs and better protection of switchgear
  • Reduced operator manual handling requirements through the development of a new sliding type bypass arrangement to isolate screenings sluice stone trap. This will also prolong the life of stone trap and reduce future maintenance costs
  • Increased operational reliability and improved isolation capability by replacing rather than refurbishing penstocks
  • Micro-tunnelling from grit excavation to existing drainage pits for improved safety in construction which will reduce the frequency of maintenance required longer term

In 2010, UGL’s system integration team received a ‘Highly Commended’ award in the National PACE Zenith awards for Water and Wastewater for their work on this project.

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