The Infrastructure Sustainability Council of Australia (ISCA) has awarded a water utility the highest sustainability rating ever achieved for an Australian water infrastructure project.
Sydney Water’s Lower South Creek Treatment Program earned an Infrastructure Sustainability (IS) Design “Excellent” rating of 69.7 points.
The program involves a $450 million upgrade of facilities at St Marys and Quakers Hill, which will see the adoption of new technologies that will make water treatment more sustainable, cost efficient and effective. Itis set to achieve a 42 per cent reduction in whole of life greenhouse gas emissions.
CEO of Infrastructure Sustainability Council of Australia, Ainsley Simpson, said, “This is the highest IS rating ever achieved for a water infrastructure project and includes numerous innovations and sustainable outcomes which other water utilities can follow and learn from. A tremendous achievement for Sydney Water.”
ISCA Case Manager, Kieren Heikkinen, added, “The outcomes were particularly impressive considering the IS rating was initially undertaken as a benchmarking exercise with little additional effort expended on sustainability, which reflects Sydney Water’s focus on sustainable outcomes. Learnings from the project and IS rating can and should be applied across Sydney Water.”
Energy and carbon forecast modelling for the project estimates that the Lower South Creek
Treatment Program will achieve a reduction of 870,000 tonnes or a 42 per cent reduction of greenhouse gas total emissions during construction and across its 50 years’ operation. This reduction includes embodied CO2 emissions from construction materials and treatment chemicals.
Onsite renewable energy use is a core objective of the Lower South Creek Treatment Strategy, with the consolidated solids processing at St Marys implemented to allow for anaerobic digestion and energy recovery through a cogeneration plant. With onsite thermal energy recovery and electricity generation, the project is able to self-supply 69 per cent of its electricity demand.
The Lower South Creek Program is Sydney Water’s first project to trial the Infrastructure
Sustainability Council of Australia’s IS Rating tool and certification process. This process has provided independent third-party assurance of sustainability outcomes in the delivery of the project.
Lead Environmental Scientist at Sydney Water, Gill Fowler, said embarking on the IS journey
provided greater incentive and opportunity to challenge current process thinking and explore new ways of operating.
“This helped drive sustainability benefits, and reduced energy demand and our carbon footprint.”
To achieve Sydney Water’s first IS Rating, the program deployed many innovative processes and technologies. These included the transfer of sludge for consolidated biosolids processing and installation of mechanical primary sedimentation screens, which were Australian firsts.
Other innovations included anaerobic digestion with Thermal Hydrolysis Pretreatment at St Marys and the secondary treatment process was modified to a Nereda Aerobic Granulated Sludge bioreactor, after a successful pilot trial, at the Quakers Hill Plant.
These innovations all helped to deliver industry leading sustainability benefits which resulted in a full ten out of ten score for innovation from ISCA, with two of the innovation points awarded for exceeding the benchmarks for energy and carbon reduction, and renewable energy supply.
The Lower South Creek Delivery Partner (WSP and UGL) put forward the IS tool to benchmark the project’s sustainability performance without incurring additional capital costs. This process has provided insights into how Sydney Water policies and procedures align with best practice in the IS Rating tool.
The Lower South Creek Treatment Program used a novel approach to forecasting and benchmarking energy and carbon under the IS Rating tool. This involved comparison against robust energy benchmark data published by the Water Services Association of Australia from 245 wastewater treatment plants across Australia and New Zealand.