Water waste

Photo by Martina Nolte

Wastewater emissions could be responsible for up to 23 per cent more emissions than currently estimated, according to a new study published in the journal Environmental Science and Technology.

The Intergovernmental Panel on Climate Change (IPCC) estimates that three per cent of the world’s emissions come from wastewater treatment. To calculate this figure, it uses a model that assumes these emissions only come from natural sources like methane from human waste. These assumptions are now being challenged by researcher Linda Tseng at Colgate University, who used radiocarbon analysis at three separate test sites around the world.

Tseng concluded that a significant amount of petroleum products were being processed through these waste treatment plants, increasing emissions by between 13 and 23 per cent. Levels of emissions differ dramatically based on the type of industry producing the wastewater, with carbon emissions the highest at the treatment facility attached to an oil refinery. The IPCC assumes that all wastewater treatment facilities produce the same amount of emissions.

“The results of this study provide an opportunity to reduce carbon dioxide emissions, including fossil carbon dioxide, from wastewater treatment facilities,” Tseng wrote in the conclusion of her report. “Strategies could include developing on-site carbon sequestration technology that runs on renewable energy.”

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