The hidden climate cost of cleaning our most precious supplies have been drastically downplayed, according to a new study.
According to research conduced by Princeton University Engineering School and Northwestern University, published in the journal Nature Water, sewage works produce around twice as many tonnes of greenhouse gases that previously believed.
Led by professors Mark Zondlo and Z. Jason Ren, in collaboration with Francesca Hopkins of UC-Riverside, water treatment facilities in the US are responsible for emitting 1.9 times the nitrous oxide gas estimated by the Environmental Protection Agency and 2.4 times the methane.
Based on these figures, plants are behind around 2.5% of all methane emissions in the United States, and 8.1% of nitrous oxide output. These gases are linked to some 22% of all global warming that has occurred since 1850.
‘We want clean water,’ Zondlo said. ‘But there is another side of the issue, and air emissions have not received the same attention that water does.’
While the numbers are alarming, the team managed to hone in on a small number of sewage works as the culprits. Taking steps to bring these sites up to the standards of others, emissions are lower, could therefore have an outsized impact on overall nitrous oxide and methane pollution. By understanding the problems with these plants, other countries can achieve the same thing, if necessary,
Much wastewater infrastructure has not been factored into air quality assessments, and often atmospheric pollution levels are not monitored on-site. This suggests simple steps could have a significant impact both on the real world footprint and understandings of national greenhouse gas emissions and climate challenges.
Image: Bob Brewer / Unsplash
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