『Abstract
　Excess PO4^3- from agricultural subsurface drainage and runoff degrades the overall water quality of the receiving surface waters in a cumulatively damaging process known as eutrophication. In the past 25 years, PO4^3- removal by industrial byproducts and minerals has received considerable attention because these materials are both abundant and inexpensive. In this study, the saturated falling-head hydraulic conductivity and phosphate removal capability of granulated blast furnace slag (GBFS), cement kiln dust (CKD), zeolite, silica sand, and coconut shell activated carbon (CS-AC) were assessed. GBFS, zeolite, silica sand, CS-AC, and 5:95％ and 10:90％ CKD/sand blends all exhibited hydraulic conductivities≧0.001 cm/s. GBFS and the CKD/sand blends exhibited＞98％ PO4^3- removal while CS-AS removed 70-79％ of initial PO4^3- concentrations. In contrast, silica sand and zeolite removed 21-58％ of PO4^3-. The phosphate removal data for each material was modeled against the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Frumkin sorption isotherms to yield insight into possible removal mechanisms. Overall, GBFS, CKD, zeolite, silica sand, and CS-AC were sufficiently permeable and removed significant amounts of PO4^3- and should be considered for use in treatment of agricultural effluent.
Keywords: Phosphate; Sorption; Industrial byproducts; Activated carbon; Slag; Zeolite』

1. Introduction
2. Methods
　2.1. Industrial byproducts and minerals
　2.2. Saturated hydraulic conductivity
　2.3. PO4^3- sorption batch experiments
　2.4. Isotherm modeling
3. Results
　3.1. Hydraulic conductivity/permeability
　3.2. Batch-sorption experiments
　3.3. Isotherm model fits
4. Discussion
5. Conclusions
Acknowledgments
References