Speakers

Speaker 1 (S1): Dilini Seneviratne, Senior Engineer – Sewerage Planning (Melbourne Water)
Speaker 2 (S2): Peter Wardrop, Engineer (Melbourne Water)

[On-screen visual: View of sludge drying pans at a sewage treatment plant. Overlaid text reads ‘Real Greenhouse Gas Emission Measurement and Reporting Program, Melbourne Water’]

S1: Right now, we’re at a point where the actions we take in the next decade will define our future. 

[On-screen text: Dilini Seneviratne, Melbourne Water, Senior Engineer – Sewerage Planning]
[On-screen visual: Dilini standing on site at a treatment plant.]

S1: At Melbourne Water, we have pledged to halve our emissions by 2025 and reduce them to net zero by 2030. 

[On-screen visual: Close-up of aerators and bubbling effluent in a sewage treatment lagoon, cutting across to drone footage of sludge drying pans]

S1: We’re already increasing our use of renewable energy, but we also need to reduce our direct emissions – like those created through the treatment of sewage. 

[On-screen visual: Peter walks through the Eastern Treatment Plant, looking at the sewage treatment infrastructure. Scene cuts to back to Dilini.]

S1: Historically, we haven’t had a complete view of these kinds of emissions, so we were limited in how we could improve our abatement strategies. That’s why we began our Real Greenhouse Gas Emission Measurement and Reporting Program.

S1: We partnered with experts at the University of Melbourne, the University of Queensland, Ektimo and Haliburton Scientific. And we worked together to develop new methods to measure and report direct emissions from three major sources at our sewage treatment plants. 

[On-screen text: Peter Wardrop, Melbourne Water, Engineer]

S2: The first project established a novel hood and gas analyser system for measuring nitrous oxide emissions from aerated nitrogen removal systems. 

[On-screen visual: Peter inspects equipment at the Western Treatment Plant. A close-up of the equipment is labelled with the Ektimo logo, and reads ‘Continuous Emission Monitoring System’.]

S2: What we’ve found through this project is that actual emissions don’t equal what we’re reporting. So, results to date have shown that emissions vary significantly from season to season, and this proves that relying on the existing reporting guidelines for nitrous oxide is problematic.

S2: Using these insights, we’re continuing to work with others such as Icon Water and the University of Queensland, so that we can increase our understanding of the factors that influence these emissions – in order to identify new abatement strategies.

[On-screen visual: Dilini standing at a sewage treatment plant]

S1: The second project measured methane emissions from open air sludge drying – a significant contributor to our direct emissions. 

[On-screen visual: Aerial footage of monitoring equipment set up between two sludge drying pans at the Eastern Treatment Plant]

S1: To build a business case for alternative processes, we conducted an Australian first two-year monitoring campaign covering the entire drying process. Fixed laser measurement, meteorological data and inverse dispersion modelling were used to monitor these emissions at our Eastern Treatment Plant. This has led to the development of a model that estimates methane emissions from these drying pans. 

[On-screen visual: Peter standing at a sewage treatment plant]

S2: Thirdly, we deployed plant wide and operating area wide techniques to uncover methane emissions from lesser-known sources at our Eastern Treatment Plant. 

[On-screen visual: Aerial footage of an old sewage treatment lagoon at the Eastern Treatment Plant.]

S2: This included using a gas tracer test on one of the sludge drying pans. And this identified emissions from an old lagoon system. 

S2: We plan to further refine these techniques and deploy them to other areas. 

[On-screen visual: Dilini standing at a sewage treatment plant]

S1: This program has developed an unprecedented framework in Australia for investigating and quantifying emissions at sewage treatment plants. 

[On-screen visual: Dilini and Peter walkthrough the coastal habitat at the Western Treatment Plant, where birds can be seen foraging in the decommissioned treatment lagoons.]

S1: Using this knowledge, other water organisations will be better equipped to tackle climate change. We look forward to continuing to work with our partners; because the more we understand about direct emissions, the stronger our abatement strategies will be – bringing us all closer to net zero.

[On-screen visual: Melbourne Water logo, accompanied by text ‘melbournewater.com.au’]