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PO4 3− Removal by and Permeability of Industrial Byproducts and Minerals: Granulated Blast Furnace Slag, Cement Kiln Dust, Coconut Shell Activated Carbon, Silica Sand, and Zeolite
- Agrawal, Sheela G., King, Kevin W., Fischer, Eric N., Woner, Dedra N.
- Water, air, and soil pollution 2011 v.219 no.1-4 pp. 91
- activated carbon, cement, coconuts, furnaces, industrial byproducts, kilns, permeability, phosphates, sand, saturated hydraulic conductivity, silica, slags, sorption isotherms, subsurface flow, surface quality, surface water, water quality, water treatment, zeolites
- 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-AC 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.