Fugitive greenhouse gas emissions from wastewater systems

Current Australian practice for estimating greenhouse gas emissions from wastewater treatment focuses mainly on emissions associated with energy use (e.g. electricity and fuel consumption). Quantifying fugitive emissions from wastewater systems is an area of uncertainty for the industry, with less developed and less reliable methodologies. This level of uncertainty in the wastewater industry's profile is unacceptable in the emerging business environment of carbon pricing, and managerial commitments to neutrality. Methane and nitrous oxide emissions have much higher global warming potentials than carbon dioxide. This paper reviews existing knowledge on their production in wastewater systems and defines their relative importance compared to emissions from energy usage in wastewater systems and emissions from other economic sectors. Further areas of research were identified, to to minimise the level of uncertainty in the industry. A draft methodology for fugitive greenhouse gas emissions (GHG) from Australian wastewater systems was proposed for consideration by the Department of Climate Change (formerly known as the Australian Greenhouse Office (AGO)).