Modeling Kinetics and Isotherms of Functionalized Filter Media for Nutrient Removal from Stormwater Dry Ponds

Sorption media with mixes of some recycled materials, such as sawdust and tire crumbs, combined with sand/silt and limestone, become appealing in nutrient removal for promoting urban stormwater management with sustainability implications. This article aims to present a specific type of functionalized filter medium and examine its physicochemical process for nutrient removal with the aid of Langmuir and Freundlich isotherms and isolated filtration kinetics. Within a suite of batch tests, pollutants of concern include ammonia, nitrite, nitrate, orthophosphate, total dissolved phosphorus, etc. The potential for application in stormwater management facilities, such as dry ponds, was emphasized in terms of life expectancy and removal efficiency. When compared with the natural soil that was selected as the control case in the column tests, our ‘‘green sorption media mixture’’ with respect to three types of sorption, including adsorption, absorption, and ion exchange, proved relatively effective in terms of removing most of the target pollutants under various influent waste loads. Sensitivity analysis with respect to the pH values and initial concentrations simultaneously or separately was presented in the end to enhance the engineering reliability analysis. It shows that with the inclusion of limestone, drastic changes of pH values can be buffered well, so that the impacts on the ultimate removal efficiency of ammonia and nitrates can be isolated solely to the changes of initial concentrations. 2009 American Institute of Chemical Engineers Environ Prog, 29: 319–333, 2010