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In this study, plane and circular turbulent non-buoyant jets are simulated numerically using a threedimensional computational model. The aim of the study is to evaluate the accuracy of turbulent closure schemes employed in three-dimensional models. In particular, standard k−ε and renormalized group k−ε schemes with standard coefficients are evaluated. The modeled jets are deeply submerged, that is the impact of free surface and solid boundaries on jets are eliminated. The accuracy of the turbulent schemes is assessed by analyzing the decay of centerline velocity, jet growth rates, similarity of longitudinal and vertical velocity profiles, and turbulent kinetic energy profiles. The results from the two turbulent closure schemes are compared with accepted experimental and theoretical studies to determine their accuracy. It is found that the k−ε scheme with standard coefficient performs equally well and in some cases better than the renormalized group k−ε scheme. Finally, the model is applied to analyze flow pattern in the Sampit River, South Caroline, USA, resulting from stormwater discharge in a recreational area. Various inlet designs are investigated and box inlet is found to provide a practical means of localizing high surface currents.

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The 1994 Everglades Forever Act mandates the South Florida Water Management District and the Florida Department of Environmental Protection to evaluate a series of advanced treatment technologies to reduce total phosphorus (TP) in Everglades Agricultural Area runoff to a threshold target level. A submerged aquatic vegetation/limerock (SAV/LR) treatment system is one of the technologies selected for evaluation. The research program consists of two phases. Phase I examined the efficiency of SAV/LR treatment system for TP removal at the mesocosm scale. Preliminary results demonstrate that this technology is capable of reducing effluent TP to as low as 10 microg/L under constant flows. The SAV component removes the majority of the influent soluble reactive P, while the limerock component removes a portion of the particulate P. Phase II is a multi-scale project (i.e., microcosms, mesocosms, test cells and full-size wetlands). Experiments and field investigations using various environmental scenarios are designed to (1) identify key P removal processes; (2) provide management and operational criteria for basin-scale implementation; and (3) provide scientific data for a standardized comparison of performance among advanced treatment technologies.

Wastewater treatment wetlands are aquatic systems where diverse dissolved organic matter (DOM) compositions physically interact. Complex photochemical behaviors ensue, leading to uncertainties in the prediction of indirect photodegradation rates for...