Efficacy of selected phosphorus sorbing materials (PSMs) to enhance the orthophosphate sorption capacity of filter socks

Agricultural phosphate (PO 4 3− ) is a major cause of water quality compliance failures. Filter socks (FS) are a sediment‐control method proven to be effective at removing sediment and sediment bound‐P. Within the water and wastewater treatment industries phosphorous sorbing materials (PSMs) are widely used to remove reactive PO 4 3− . Combining PSMs with FS provides an opportunity to concomitantly remove sediment, sediment bound‐P and PO 4 3− from agricultural runoff. A column experiment was undertaken to evaluate the efficacy of selected PSMs to remove PO 4 3− across a range of PO 4 3− concentrations (0.08, 0.26 and 1.3 mg/L) and contrasting FS fill media (PAS 100 Compost and Woodchip). The results indicate that Ca‐enriched ferrihydrite removed up to 99% of PO 4 3− , and was the only PSM to reduce PO 4 3− to below the target value of <0.05 mg/L. An initial cost‐benefit analysis indicates that PSM‐enhanced FS are a viable option to remove PO 4 3− from agricultural runoff.