Wastewater treatment produces Greenhouse gas emissions through aerobic or anaerobic decomposition. If methane is recovered from wastewater treatment facilities as an energy source, it is reported under Stationary Energy
Wastewater emissions are calculated by scaling state level data from Australia’s National Greenhouse Accounts to the municipal level. For the residential sector, wastewater is scaled by the ratio of population of municipality relative to the state. For the commercial and industrial sector, wastewater is scaled by the ratio of industrial jobs of municipality relative to the state.
In line with the GPC, wastewater emissions are calculated at the point of generation rather than treatment. This enables regions who do not have wastewater treatment facilities within their boundary to understand the impacts of wastewater generated locally. This is similar to the approach taken for electricity whereby emissions are counted by the region in which the electricity is used rather than where the power plant is located.
For more information on Wastewater calculations please see the Methodology document which can be downloaded from the Resources page.