Phosphorus removal from Everglades agricultural area runoff by submerged aquatic vegetation/limerock treatment technology: an overview of research

Abstract

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.

Environmental conditions and phosphorus removal in Florida lakes and wetlands inhabited by Hydrilla verticillata (Royle): implications for invasive species management

“…However, the hydraulic loading and total P settling rates for the Hydrilla period were comparable to those in STA-1W Cell 4, which had been dominated by Najas. Because the settling rate for the Hydrilla period was calculated on performance data for a period of 2 years compared to 5 years for STA-1W Cell 4 and because wetlands tend to exhibit a higher rate of P removal during ''start-up'' periods (Gu et al 2001), more data are needed to further evaluate the performance for different plant types in constructed wetlands. …”

“…This implies that other factors such as seed availability, lake drawdown, plant die-off and weed control (herbicide and mechanical removal) might also influence the abundance of Hydrilla. Nutrient removal efficiency from constructed wetlands and natural systems can also be affected by the above factors as well as other hydraulic and management issues (Gu et al 2001;Dierberg et al 2001). Therefore, the results from this study may be complicated by some factors that cannot be quantified and included in this analysis.…”

“…Total P settling rates were obtained from Kadlec and Knight (1996) for the emergent marsh, Nungesser and for STA-1W Cell 3, an STA dominated by cattail (Typha latifolia L.) and several submerged plants, Gu et al (2001) for STA-1W Cell 4 and Knight et al (2003) for selected Florida lakes dominated by submerged macrophytes. The settling rate for STA-1W Cell 5 was calculated using the following equation (Kadlec and Knight, 1996):…”

The accumulation of alkylphenols in submersed plants in spring in urban lake, China

“…higher transparence, lower suspension solids and chlorophyll etc., than the lake without plants (O'Dell et al, 1995). Furthermore submersed plants have also been used in wastewater treatment for reducing the nutrient elements due to accumulation considerable amounts of nitrogen, phosphate and metals in their tissues (Gu et al, 2001;Thoren et al, 2004;Duman et al, 2006). However, little is known about AP accumulation by submersed macrophytes.…”

Community Structure and Environmental Conditions in Florida Shallow Lakes Dominated by Submerged Aquatic Vegetation

“…Briefly, SAV is capable of stabilizing sediments, reducing flow velocity, providing habitat for aquatic animals and assimilating nutrients that might otherwise be used by bloom-forming phytoplankton under favorable environmental conditions. Recently, interest in using SAV for nutrient reduction from stormwater treatment systems has grown , Gu et al 2001. Phosphorus (P) removal occurs through plant uptake and photosynthetically induced co-precipitation with calcium carbonate under high pH (Murphy et al 1983, Dierberg et al 2002.…”