title: Biochar and activated carbon for enhanced trace organic contaminant retention in stormwater infiltration systems.
abstract: To assess the effectiveness of biochar and activated carbon (AC) for enhanced trace organic contaminant (TOrC) retention in stormwater infiltration systems, an approach combining forward-prediction modeling and laboratory verification experiments was employed. Batch and column tests were conducted using representative TOrCs and synthetic stormwater. Based on batch screening tests, two commercially available biochars (BN-biochar and MCG-biochar) and an AC were investigated. The AC exhibited the strongest sorption, followed by MCG-biochar and BN-biochar. Langmuir isotherms provided better fits to equilibrium data than Freundlich isotherms. Due to superior sorption kinetics, 0.2 wt % MCG-biochar in saturated sand columns retained TOrCs more effectively than 1.0 wt % BN-biochar. A forward-prediction intraparticle diffusion model based on the Langmuir isotherm adequately predicted column results when calibrated using only batch parameters, as indicated by a Monte Carlo uncertainty analysis. Case study simulations estimated that an infiltration basin amended with F300-AC or MCG-biochar could obtain sorption-retarded breakthrough times for atrazine of 54 or 5.8 years, respectively, at a 1 in./h infiltration rate. These results indicate that biochars or ACs with superior sorption capacity and kinetics can enhance TOrC retention in infiltration systems, and performance under various conditions can be predicted using results from batch tests.
authors.affiliation: †Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States.
authors.forename: Bridget A
authors.initials: BA
authors.lastname: Ulrich
authors.affiliation: †Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States.
authors.forename: Eugenia A
authors.initials: EA
authors.lastname: Im
authors.affiliation: ‡School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Werner
authors.affiliation: †Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Higgins
mesh_terms: D000327:Adsorption; D002138:Calibration; D002606:Charcoal / Q000737:chemistry*; D055867:Cyclonic Storms; D007700:Kinetics; D008962:Models, Theoretical; D009930:Organic Chemicals / Q000032:analysis*; D011891:Rain; D012015:Reference Standards; D014230:Triazoles / Q000032:analysis; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009930:Organic Chemicals; D014230:Triazoles; D014874:Water Pollutants, Chemical; C540010:biochar; D002606:Charcoal; C012771:benzotriazole