Treatment of highway runoff : engineered filter media for pollutant removal through enhanced sorption : final report.

PDFTech ReportFHWA-GA-16-11-23RP 11-23T.O. 02-102RP 11-23PI# 0010765SorptionRunoffWater quality managementSewage treatmentPollutantsPollution controlFiltrationGrassesNitrogenSoilsBiofiltrationnative grassesUnited StatesGeorgiaGeorgia. Dept. of Transportation. Office of ResearchBurns, Susan E.Caruso, Nicole T.Georgia Institute of Technology. School of Civil and Environmental EngineeringGeorgia. Dept. of Transportation. Office of ResearchUnited States. Federal Highway AdministrationUS Transportation CollectionThe work performed in this study focused on the investigation of the use of engineered biofiltration layers to enhance the removal of roadway stormwater runoff contaminants (specifically nutrients, solids, heavy metals, and pH). Six Georgia native grasses as well as one turf grass were tested in the column study, along with a permanently saturated zone for biofiltration enhancement. Results indicated that Big Bluestem, Indian grass, and Switchgrass, when paired with a permanently saturated zone, removed the highest percentage of total nitrogen across all experiments (4%, 13%, and 18% respectively). These species contained thick and dense root systems that spanned the entire length of the biofilter column. Removal of nitrate was enhanced with a saturated zone, while ammonium removal decreased. A permanently saturated zone increased removal of phosphorus, copper, and zinc (removal of lead was >97% in all cases. The results demonstrate that the addition of active biofiltration layers to BMPs on GDOT right-of-ways can be an important component in the reduction of contaminant loading in stormwater that is being discharged to environmentally sensitive environments