水処理の気候コストを評価（Understanding the climate cost of cleaning our water）

2025-10-08 ノースウェスタン大学

＜関連情報＞

• https://news.northwestern.edu/stories/2025/10/understanding-the-climate-cost-of-cleaning-our-water
• https://www.nature.com/articles/s44221-025-00485-w

米国の廃水処理からの温室効果ガス排出量をベンチマークし、削減目標を設定する Benchmarking greenhouse gas emissions from US wastewater treatment for targeted reduction

Sahar H. El Abbadi,Jianan Feng,Abigayle R. Hodson,Maryam Amouamouha,Margaret M. Busse,Christina Polcuch,Pengxiao Zhou,Jordan Macknick,Jeremy S. Guest,Jennifer R. Stokes-Draut & Jennifer B. Dunn
Nature Water  Published:08 October 2025
DOI:https://doi.org/10.1038/s44221-025-00485-w

Abstract

Here, to assess the national climate impact of wastewater treatment and inform decarbonization, we assembled a comprehensive greenhouse gas inventory of 15,863 facilities in the contiguous USA. Considering location and treatment configurations, we modelled on-site CH₄, N₂O and CO₂ production and emissions associated with energy, chemical inputs and solids disposal. Using Monte Carlo simulations, we estimated median national emissions at 47 million tonnes of CO₂ equivalent per year, with on-site process CH₄ and N₂O emissions exceeding current government estimates by 41%. Treatment configurations with anaerobic digesters are responsible for 16 million tonnes of CO₂ equivalent per year of fugitive methane, outweighing benefits achieved through on-site electricity generation. Systems designed for nutrient removal have the highest greenhouse gas emissions intensity, attributable to energy requirements and N₂O production, demonstrating current trade-offs between meeting water quality and climate objectives. We analysed key sensitivities and included a geospatial analysis to highlight the scale and distribution of opportunities for reducing life cycle greenhouse gas emissions.