Study Reveals Rivers Emit 5x More Methane Post Wastewater Treatment

A recent study shows that a river receiving treated wastewater emits five times more methane than a river without such discharge. Researchers Ida Peterse and Lisanne Hendriks from Radboud University conducted this study, which is published in the journal Science of The Total Environment.

The researchers measured methane emissions at different points along the Linge and Kromme Rijn rivers. They used a floating chamber to collect gases from the water surface and analyzed their composition. They measured emissions 500 meters before the wastewater treatment plant, at the discharge point, and up to two kilometers downstream. They found that methane emissions peaked two kilometers after the discharge point, reaching levels five times higher than at the point of discharge.

Although the treated water meets Dutch standards, it still affects the river’s ecology. The treated water contains nitrogen, phosphate, and carbon, which promote algae growth. When algae die and decompose, they create conditions favorable for methane-producing microorganisms.

Peterse emphasized that while the discharged water may meet standards, it still increases methane emissions. Since rivers contribute significantly to global methane emissions, this issue is crucial to address. This research highlights the need for greater awareness of the environmental impact of wastewater discharge on ecosystems.

For more details, see the study by Ida F. Peterse et al., titled Wastewater-effluent discharge and incomplete denitrification drive riverine CO₂, CH₄, and N₂O emissions in Science of The Total Environment. DOI: 10.1016/j.scitotenv.2024.175797.