Submitted to: Journal of Water Air and Soil Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2010
Publication Date: 1/19/2011
Citation: Agrawal, S.G., King, K.W., Fischer, E.N., Woner, D.N. 2011. PO43 Removal by and Permeability of Industrial Byproducts and Minerals: Granulated Blast Furnace Slag, Cement Kiln Dust, Coconut Shell Activated Carbon, Silica Sand and Zeolite. Journal Of Water Air And Soil Pollution. DOI 10.1007/s11270-010-0686-4.
Interpretive Summary: Excess concentrations of phosphate from subsurface drainage degrades the overall water quality of the receiving surface waters in a cumulatively damaging process referred to as eutrophication. Previous research has indicated that end-of-tile filter cartridges may significantly reduce phosphate delivery to surface waters. In this study, we investigated several industrial byproducts and two minerals, as potential filter media. The findings of this study show that blast furnace slag, cement kiln dust, activated carbon, zeolite, and silica sand are all capable of removing significant amounts of phosphate. The phosphate sorption behavior of these materials can also be modeled against several sorption isotherm models. Overall, we conclude that these materials are suitable filter media which can be used in an end-of-tile filter cartridge.
Technical Abstract: Excess aqueous concentration of phosphate degrades the overall water quality of the receiving surface waters in a cumulatively damaging process referred to as eutrophication. Adsorption of excess phosphate has proven to be the most effective, and economical methods of phosphate removal from such waters. In the past 25 years, adsorption of phosphate by industrial byproducts and natural materials like blast furnace slag, coconut-derived activated carbon, and zeolite has received considerable attention because these materials are abundant and inexpensive. In this study, the saturated falling-head hydraulic conductivity and batch phosphate sorption 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% phosphate removal while CS AC removed 70% -79% of initial phosphate concentrations. In contrast, silica sand and zeolite removed 21%-58% of phosphate. The sorption data for each material was modeled against the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Frumkin isotherms to yield insight into possible sorption mechanisms and maximum sorption capacity. Overall, GBFS, CKD, zeolite, silica sand, and CS AC inexpensively removed significant amounts of PO43- and should be thus considered for use in water quality management.