Water quality and hydraulic performance of biochar amended biofilters for management of agricultural runoff

This research evaluated the effect of biochar amendment rate on nitrogen species and organic carbon removals hydraulic performance in biofilter columns treating dairy farm runoff. Initial studies compared sand amended with two types different specific surface area (SA) cation exchange capacity (CEC) an un-amended column. The results showed that enhanced N-species removal due to its unique physicochemical properties. In subsequent tests, fractions (20% 50% by volume) were operated at varying loading rates antecedent dry conditions. Total nitrogen, ammonia, significantly higher column fraction. high CEC increased ammonium retention during application period, allowing for nitrification periods (ADPs) when aerobic conditions developed media pores. High SA also resulted greater DON DOC adsorption. A variable saturation flow model biofiltration was using HYDRUS-1D software. calibrated data from conservative tracer moisture content studies. Model microporous structure increases time needed reach full saturation, lowers saturated conductivity medium. can be used design field scale systems managing agricultural