Wastewater plants emit more greenhouse gases than estimated

Wastewater plants emit double the methane and nitrous oxide estimated by EPA, study finds.

Why it matters

  • Wastewater plants contribute more to greenhouse gas emissions than previously thought.
  • Targeted interventions at high-emission plants could significantly reduce overall emissions.

By the numbers

  • Emissions are 1.9 times higher for nitrous oxide and 2.4 times higher for methane than EPA estimates.
  • Wastewater plants contribute 2.5% of U.S. methane emissions and 8.1% of nitrous oxide emissions.
  • Researchers sampled 96 plants and drove 52,000 miles to collect data.

The big picture

  • Current EPA estimates may undercount wastewater plant emissions.
  • Variability in emissions suggests targeted interventions could be effective.

What they're saying

  • Some comments question the accuracy of EPA estimates and the methodology of the study.
  • There's interest in the potential financial incentives for reducing emissions.

Caveats

  • Study based on a subset of plants; emissions can vary with conditions.
  • More comprehensive monitoring may be needed for accurate national estimates.

What’s next

  • Work with plant operators to identify high-emission processes.
  • Explore capture of methane and nitrous oxide as potential revenue streams.