Doctor of Philosophy (PhD)
Civil and Environmental Engineering
This study examined the influence of hydrology on rainfall runoff phosphorus partitioning between aqueous and particulate-bound phase, and dissolved phosphorus speciation at the upper end of a Cementitious Porous Pavement (CPP) small urban watershed. This study also investigated particulate bound phosphorus temporal distribution during storm event and phosphorus equilibrium distribution on a wide gradation of solids captured by hydrodynamic separator after the storm completed. Results indicate that EMC of urban rainfall runoff phosphorus exceeds EPA water quality criteria, with majority of particulate-bound phosphorus while rainfall by itself contains non-comparable low concentration of phosphorus. Dissolved phosphorus was mainly H2PO4- and HPO4-2 by Minteq modeling. Equilibrium granulometric distribution indicated that particulate-bound phosphorus sorption capacity ranging from 0.82 to 3.4 mg/g, increases with deceasing solids size. This study also investigated pollutant transport modeling of particulate-bound phosphorus in urban rainfall-runoff and in-situ removal mechanism and efficiency by hydrodynamic separator on the basis of representative sampling and appropriate P measurement. Treatment of P by hydrodynamic separator is a combination of dynamic screening and quiescent settling. In the range of 10 ~ 50%, overall P removal efficiencies depend pronouncedly on size and distribution of particulate matter. P pollutant power law model could be successfully applied for intra-event P transport in urban rainfall-runoff. Isotherm, kinetics and breakthrough of adsorption of phosphorus from synthetic rainfall-runoff onto highly porous aluminum oxide coated media (AOCM) were investigated. Under the typical simulated runoff conditions, AOCM showed high adsorption capacity for P. Freundlich isotherm could successfully represent isotherm data. The kinetics of P adsorption on AOCM was fast, with the reactions completed within the first few hours, sometimes even within minutes. Pseudo second order reaction model fitted the kinetics data best under all experimental conditions and intraparticle diffusion model could be successfully applied for the first hour P adsorption kinetics. Bed volumes at breakthrough are in terms of hundreds and at exhaustion of double or triple value. Empirical and mechanistic models were found good applicability. Cost effective AOCM are capable of efficient treatment for urban rainfall runoff P.
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Ma, Jia, "Speciation, Equilibrium Distribution and Kinetics of Rainfall-Runoff Phosphorus in Adsorptive-Filtration Unit Operations and Processes" (2005). LSU Doctoral Dissertations. 1961.
John J. Sansalone