MELBOURNE, Oct. 8 (Xinhua) -- Wastewater treatment plants are releasing far more ammonia into the atmosphere than previously recognized, an Australian study finds.
Agriculture is the largest contributor to atmospheric ammonia, but researchers have confirmed sludge drying pans, a common fixture in treatment plants, also release ammonia gas, an emission generally overlooked in wastewater operations, according to Australia's University of Melbourne-led study published Wednesday in Nature Water.
The research shows that ammonia emitted from sludge drying can transform into nitrous oxide, a potent greenhouse gas, which causes environmental harm such as soil acidity, nutrient accumulation in waterways, and formation of particulate matter that poses human health risks.
"Ammonia is a 'sticky' gas, meaning it is highly reactive and readily absorbs to any surface," said University of Melbourne Research Fellow Bai Mei.
Researchers combined advanced monitoring techniques to estimate 43 tons of ammonia were emitted from the pan over a two-year sludge drying cycle, representing nearly 95 percent of nitrogen-based emissions from the drying pan and 6-9 percent of total nitrogen at the treatment plant.
The study highlights the need to rethink wastewater management practices to transition to different sludge drying methods to mitigate ammonia emissions, and address their broader climate and ecological impacts, Bai said. ■
