HR: 0800h
AN: H41A-0289    [Abstracts]
TI: Rejuvenating the Largest Treatment Wetland in Florida: Tracer Moment and Model Analysis of Wetland Hydraulic Performance
AU: White, J R
EM: jrwhite@lsu.edu
AF: Wetlands Biogeochemistry Institute, Louisiana State University, Baton Rouge, LA 70803
AU: * Wang, H
EM: whuaguo@mail.ifas.ufl.edu
AF: Soil and Water Science Department, University of Florida 2169 McCarty Hall, Gainesville, FL 32511
AU: Jawitz, J W
EM: jwjawitz@ifas.ufl.edu
AF: Soil and Water Science Department, University of Florida 2169 McCarty Hall, Gainesville, FL 32511
AU: Sees, M D
EM: msees@intellistar.net
AF: Public Works Department, City of Orlando, Orlando, FL 32801
AB: The Orlando Easterly Wetland (OEW), the largest municipal treatment wetland in Florida, began operation in 1987 mainly for reducing nutrient loads in tertiary treated domestic wastewater produced by the city of Orlando. After more than ten years of operation, a decrease in total P removal effectiveness has occurred since 1999, even though the effluent concentration of the wetland has remained below the permitted limit of 0.2 mg/L,. Hydraulic inefficiency in the wetland, especially in the front-end cells of the north flow train, was identified as a primary cause of the reduced treatment effectiveness. In order to improve the hydraulic performance of the OEW and maintain its efficient phosphorus treatment, a rejuvenation program (including muck removal followed by re-vegetation) was initiated on the front-end cells of the north flow train in 2002. The effectiveness of this activity for the improvement of hydraulic performance was evaluated with a tracer test and subsequent moment and model analyses for the tracer resident time distribution (RTDs). Results were compared to similar tracer tests conducted prior to rejuvenation activities. The models included one-path tank-in-series (TIS), two-path TIS, one-dimensional transport with inflow and storage (OTIS), plug flow with dispersion (PFD), and plug flow with fractional dispersion (PFFD). The hydraulic performance was characterized by both wetland hydraulic efficiency and the spreading of tracers. The results demonstrated that the rejuvenation considerably improved the hydraulic performance in the restored area. Also presented is a comparison of the wetland response between both bromide and lithium tracers, and the determination of the complete moments of residence time distributions (RTD) in cell-network wetlands.
DE: 1871 Surface water quality
DE: 1890 Wetlands
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting