Research: Development of Reactive Geocomposite Mat Containing Stell Slag and Mulch for Removal of Phosphate and Nitrate from Impacted Waters

Research: Development of Reactive Geocomposite Mat Containing Steel Slag and Mulch for Removal of Phosphate and Nitrate from Impacted Waters

Dr. Treavor H. BoyerAssociate ProfessorArizona State University

Friday, September 21, 2018

This project develops an enabling technology for biogeochemical processes specifically targeted towards the adsorption and precipitation of phosphate ion and the biological denitrification of nitrate ion in a reactive geocomposite mat for application for remediation of groundwater and surface water. More broadly, this project explores the coupling of physical-chemical processes with microbiological processes to treat impacts waters containing multiple contaminants. The reactive geocomposite mat incorporates basic oxygen furnace steel slag and organic waste material (e.g., woody mulch) with a geotextile to create a mat that can be rolled out and underlay an infiltration basin. The chemistry of the mat is driven by the slag, which facilitates adsorption, chelation, and precipitation of phosphate with constituents that leach from the slag including calcium, silica, and alkalinity. In addition to facilitating physical-chemical processes, the high pH conditions of the mat pore water facilities the breakdown of the organic waste material, which in turn can serve as substrate for denitrifying bacteria. The challenge, which is the focus of the current project, is balancing the water chemistry conditions such that both phosphate adsorption/precipitation occurs (generally at highly alkaline pH) and nitrate denitrification occurs (generally at neutral to slightly alkaline pH). This presentation will highlight results from year 1 and discuss plans for year 2.

Presenter Bio
Dr. Treavor H. Boyer is an Associate Professor in the School of Sustainable Engineering and the Built Environment (SSEBE) at ASU, and is Program Chair of the new Environmental Engineering undergraduate degree program at ASU. His research interest is water quality and treatment with numerous research projects on innovative applications of physical-chemical treatment technology applied to alternative water sources and resource recovery. Dr. Boyer is the recipient of an NSF CAREER Award and his research has been sponsored by federal agencies including the EPA centers Water Innovation Network for Sustainable Small Systems (WINSSS) and Center for Reinventing Aging Infrastructure for Nutrient Management (RAINmgt). Dr. Boyer earned his Ph.D. and M.S. degrees in environmental engineering from the University of North Carolina at Chapel Hill, and his B.S. degree in chemical engineering from the University of Florida. Dr. Boyer was previously an Assistant Professor and Associate Professor in the Department of Environmental Engineering Sciences at the University of Florida.