PARENT SESSION
Poster Session # 17: Aquatic Systems.
Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Implications of water velocity for phosphorus capture by Stormwater Treatment Areas in the Florida Everglades.
Simmons, Steven*,1, Owen, Dianne1, Volin, John1, 1 Florida Atlantic University, Davie, FL
ABSTRACT- Artificial wetlands are increasingly being used as filters of wastewater with high nutrient loads. This is especially true in Florida, where Everglades restoration includes construction of six Stormwater Treatment Areas (STAs) totaling 16,000 hectares. The primary objective of this research was to investigate the effects of water movement on phosphorus uptake by periphyton. Our hypothesis was that phosphorus uptake by a periphyton-dominated system would correlate positively with water velocity. We tested this hypothesis within constructed mesocosms that allowed us to test the sole effect of flow rate, keeping other factors, such as hydraulic retention time and hydraulic loading rate, equal across treatments. Treatment water velocities were approximately 0.22 cm s-1 and 2.0 cm -1, which are achievable levels within an STA. The mesocosms were installed at the outlet of an STA and thus received water from which much of the biologically available phosphorus had already been assimilated. After twelve weeks of treatment, biomass in the high flow rate was 20% higher than that in the low flow rate. Plant tissue phosphorus did not differ significantly between the two treatments. The greater biomass accrual in the fast treatment therefore represents a greater removal of phosphorus from the water column. Information obtained from this study can be used to optimize water movement within STAs, leading to greater operational efficiencies and a lower final concentration of phosphorus in water discharged to the Everglades.
Key words: periphyton, phosphorus, Everglades