『(Abstract)
　X-ray absorption near edge structure (XANES) spectroscopy is a useful technique for characterization of chemical species of phosphorus in complex environmental samples. To develop and evaluate bed filters as sustainable on-site wastewater treatment solutions, our objective in this study was to determine the chemical forms of accumulated phosphorus in a selection of promising filter materials: Filtralite P, Filtra P, Polonite, Absol, blast furnace slag, and wollastonite. Full-scale operational wastewater-treatment systems were sampled and in addition, filter samples collected from laboratory studies provided access to additional media and complementary samples. Phosphorus species were characterized using phosphorus K-edge XANES spectroscopy, complemented by X-ray powder diffraction (XRPD) and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). No systematic differences could be seen in the results between laboratory- and full-scale samples. All six filter media contained significant amounts of crystalline calcium phosphates. Some samples also contained amorphous calcium phosphate (＞60％ of total P in Absol). In Filtralite P and blast furnace slag, more than 35％ of the accumulated phosphorus was associated with Fe or Al. Both the power and shortcomings of XANES analysis for characterizing P species in these filter media are discussed.』

Introduction
Experimental section
　　Attenuated total reflectance Fourier-transform infrared spectroscopy
　　X-ray powder diffraction
　　Preparation of XANES standards
　　Sample preparation for XANES analysis
　　XANES data collection and data treatment
　　XANES fitting analysis
Results
　XRPD and ATR-FTIR characterization of standards
　　Phosphorus phases as evidenced by XRPD
　　XANES spectra for standards
　　Phosphorus phases in filter samples as shown by XANES
Discussion
　Phosphorus speciation in filter media
　　Interpretation of XANES spectra
Acknowledgments
Supporting information available
Literature cited