As water utilities progress toward net zero commitments, accurate measurement of scope 1 emissions has become a critical technical challenge. Methane and nitrous oxide from wastewater treatment processes remain difficult to quantify at the facility scale, and current reporting frameworks rely on mass balance assumptions rather than direct measurement.
South East Water’s Aerial Fugitive Emissions Mapping project addresses this gap by introducing drone-based gas flux measurement to map emissions across a full treatment plant.
The project sought $34,000 in funding through the 2025 Water Minister’s Climate Innovation Challenge, supporting a broader program cofunded by South East Water and guided by the University of Queensland. The investment enables the first Australian deployment of this method within a complex wastewater treatment environment.
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Why do utilities need more accurate emissions data?
Wastewater treatment is one of the Victorian Government’s largest remaining sources of direct greenhouse gas emissions. While utilities have improved energy efficiency and adopted renewable power, methane and nitrous oxide emissions are still estimated rather than directly measured. This creates uncertainty in emissions inventories and limits the effectiveness of mitigation planning.
The National Greenhouse and Energy Reporting Scheme (NGERS) uses default emission factors and mass balance calculations that do not account for site-specific characteristics or process variability.
Research suggests that actual emissions may differ significantly from reported values, particularly in aeration, digestion and sludge handling processes. To plan meaningful reductions, utilities must first understand the true emissions profile of their assets.
How does drone emissions mapping work?
The project partners with Explicit, a company with extensive experience in drone-based atmospheric measurements across Europe. The method uses a drone equipped with highly sensitive sensors for carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O).
Flying at controlled altitudes and grid patterns above the treatment plant, the drone measures gas concentrations and applies flux modelling to estimate emissions from discrete areas of the site.
Unlike point sampling or in situ sensors, drone measurements capture the site-wide spatial distribution, including emissions from assets that are not commonly measured.
These may include clarifiers, sludge lagoons, aerobic and anaerobic basins, biogas storage systems and areas where leaks or bypass pathways occur.
The system meets ISO 17025 and ISO 9001 standards, providing the level of rigour needed for scientific and regulatory credibility.
Why Mt Martha Water Recycling Plant?
South East Water selected the Mt Martha Water Recycling Plant due to its complexity and diversity of treatment processes. With aerated lagoons, multiple digestion types, sludge-handling facilities, and varying operational states, it provides an ideal test environment. Mapping emissions here generates a baseline for understanding both methane and nitrous oxide generation across asset classes.
The ability to compare drone-based measurements against NGERS-reported values also enables the development of improved emission factors, supporting sector-wide refinement of modelling tools.
What insights can drone emissions mapping provide?
The project aims to deliver several technical outcomes:
- Identification of emission hotspots that are not captured by NGERS, particularly nitrous oxide from aeration basins or transitional treatment zones.
- Quantification of relative contributions of methane and nitrous oxide across processes.
- Detection of biogas leaks to support targeted maintenance and asset integrity improvements.
- Validation of fixed emission sensors, enabling smarter deployment across future monitoring programs.
- Baseline datasets for assessing upgrades and mitigation technologies, such as process optimisation or gas capture improvements.
These insights allow utilities to prioritise investments that deliver the greatest emissions-reduction impact.
What is the broader significance for Victoria?
As more treatment processes are electrified, biological emissions will account for a larger share of water sector climate impacts. Drone emissions mapping provides a scalable, low-cost, and nonintrusive method for generating real-world data across different asset configurations.
The $34,000 Challenge funding would accelerate the adoption by supporting the first full-scale drone flux deployment in an Australian wastewater context. Once established, the method can be expanded to other Victorian utilities through the Intelligent Water Networks Climate Resilience Program, further strengthening the state’s emissions inventory.
South East Water’s work demonstrates how engineering innovation can reshape the sector’s understanding of fugitive emissions. By combining advanced sensing with data-driven modelling, drone emissions mapping offers a pathway to more accurate reporting and more effective climate action across Australia.