W. Abtew, M.J. Chimney, T. Kosier, M. Guardo, S. Newman, and J. Obeysekera 1
The Everglades Nutrient Removal Project (ENR), a 1,544 ha constructed wetland, is designed to operate as a flow-through treatment system to reduce phosphorus levels in agricultural runoff/drainage that currently enters the Everglades. A portion of the runoff/drainage that originates in the Everglades Agricultural Area drainage basin is being diverted from the West Palm Beach canal into the ENR. The ENR is built on former cropland and is divided into five cells; a Buffer Cell (55 ha), Cell 1 (525 ha), Cell 2 (414 ha), Cell 3 (404 ha), and Cell 4 (146 ha). Construction was completed and the site was flooded in September 1993, however, release of treated water did not begin until August 1994 when an operating permit was granted by the EPA. The Buffer Cell distributes inflow to two independent, parallel treatment trains (Cells 1Æ3 and 2Æ4). Cell 1 and Cell 2 are naturally revegetated cattail marshes where most of the phosphorus removal is expected to occur. Cell 3 (a planted mixed marsh) and Cell 4 (a periphyton/submerged macrophyte community) are polishing cells for final reduction of phosphorus levels. Since flow-through operation began, 7,186 ha-m of water has passed through the system. Initial observations indicate that the outflow total phosphorus concentrations, on average, have been about five times lower than the inflow concentrations (ca. 100 to 200 mg L-1).
