By Diana Yates
Scientists have developed a new edge-of-field water-treatment system that reduces the load of excess nutrients washing into waterways from farm drainage systems. Their method combines a woodchip bioreactor with a two-step biochar water-treatment module. A one-year field trial demonstrated that the system reduced both nitrogen and phosphorus runoff from farmland.
The study, published in the Journal of Water Process Engineering, also included a techno-economic analysis that found that the bioreactor-biochar system could become a cost-effective alternative to current edge-of-field practices while achieving better water-quality outcomes.
Nutrient runoff from agricultural fields is a persistent contributor to water pollution, fueling harmful algal blooms and degrading freshwater and coastal ecosystems. While woodchip bioreactors are used to reduce nitrogen runoff, they are not designed to remove phosphorus, said Wei Zheng, a principal research scientist in environmental chemistry at the Illinois Sustainable Technology Center, a division of the Prairie Research Institute at the University of Illinois Urbana-Champaign. Zheng led the study with ISTC postdoctoral researcher Hongxu Zhou.
“Dissolved phosphorus is a major concern in farm drainage water,” Zheng said. “Like nitrogen, phosphorus promotes algal blooms in rivers or lakes that can produce toxins, block sunlight and deprive aquatic organisms of oxygen.”
Source : illinois.edu