10 Aug 2020
Nutrient and pesticide remediation using a two-stage bioreactor-adsorptive system under two hydraulic retention times
Damon E. Abdi, James S. Owen Jr, Julie C. Brindley, Anna C. Birnbaum, P. Chris Wilson, Francisca O. Hinza, Gemma Reguera, Joo-Young Lee, Bert M. Cregg, Daniel R. Kort, R. Thomas Fernandez
Nutrients and pesticides in irrigation return flow from agricultural operations pose an environmental risk. Water treatment systems, such as woodchip bioreactors and expanded aggregate filters, can be used to remediate these contaminants. Our objectives were to investigate agrochemical removal with these systems when operated under an extended hydraulic retention time (HRT) of 3 days and a rapid HRT of 21 minutes. A 3 day HRT effectively reduced nitrate and phosphate below 0.2 ppm in woodchip bioreactors and expanded shale filters, respectively; while a 21 minute HRT was sufficient for removing 50-75% of influent pesticide content but not for nutrient removal.