Water Resources Research Act Program

Details for Project ID 2013DE251B

Exploring the Viability of Biochar to Treat Stormwater

Institute: Delaware
Year Established: 2013 Start Date: 2013-03-01 End Date: 2014-02-28
Total Federal Funds: $1,500 Total Non-Federal Funds: $3,000

Principal Investigators: Paul Imhoff, Naomi Chang

Abstract: According to the NDPES permitting program, stormwater discharge from roadways in Delaware are point sources and therefore subject to regulation. Total Maximum Daily Load (TMDL) is the maximum amount of a pollutant that a body of water can receive while still meeting water quality standards. Within Delaware, TMDL regulations require all point source discharges of nitrogen and phosphorus to be reduced systematically. A common best management practice (BMP) to reduce nutrient pollution from stormwater is a bioretention system. A major issue with bioretention systems is their inefficiency in reducing nitrogen concentrations. It is possible for nitrate concentrations to increase within a bioretention system due to microbial nitrification of organic nitrogen and ammonium. Two other BMPs used to treat stormwater runoff from roadways are bioswales and sand filters. Although they are more efficient at removing nutrient pollution than bioretention systems, their removal rates for nutrients are still small. Ongoing research at the University of Delaware on the application of biochar to BMPs has shown that the addition of biochar significantly reduces the amount of ammonium nitrogen within synthetic stormwater. A laboratory column with 10% poultry litter biochar and 90% sand resulted in a 50% reduction in ammonium nitrogen. Because of these promising preliminary data, further evaluation of the utility of poultry litter biochar for removing ammonium from stormwater treatment media will be done.