Common Buckthorn Engineered Biochar (Rhamnus Cathartica), Calcined Quagga Mussel Shells (Dreissena Rostriformis), Pickled Steel, and Steel Slag as Filter Media for the Sorption of Phosphorus from Agricultural Runoff

The reuse of waste residuals as reactive media is a sustainable solution to remove phosphorus (P) from wastewater and reduce eutrophication. Large reactive waste media filters incorporated in edge-of-field treatment systems could reduce P loading from agricultural fields. We measured the treatment potential of regionally available waste residuals (i.e., calcined quagga mussel shells (CSHELL), magnesium activated biochar (MGBC), pickled steel (PSTEEL), and steel slag (SLAG)) for dissolved P removal. CSHELL and MGBC had elevated sorption capacities (64,419 and 50,642 mg kg−1, respectively) in comparison to SLAG and PSTEEL (14,541 mg kg−1 and 736 mg kg−1, respectively). However, CSHELL requires long reaction times for removal (22% removal after 1.5 h) and P sorbed to MGBC is removed with DI, reducing treatment potential. SLAG and PSTEEL were the only media with significant reductions of agricultural runoff and had the greatest overall treatment potential. SLAG is recommended for removal and replacement systems while PSTEEL is suitable for larger systems designed for regeneration on site.