Comparative Evaluation of Floating Treatment Wetlands for Nutrient Removal and Algal Toxin Control in Wet Detention Ponds

Abstract

Stormwater nutrient removal is a major contributor to the loadings in natural waterbodies, and any system not protected by the state or less than 10 acres, operate without water quality indefinitely. The permits do not require monitoring by private owners, but the effects are considered to be a contributor to the eutrophication of waterbodies across the world. Biomanipulation (biological mitigation) with the emerging technology, the Floating Treatment Wetland (FTW) can be used to remove nutrients, while preserving aquatic ecosystem structures with native aquatic plants. However, logistical concerns arise if the mitigation does not achieve an enhanced removal or even negative removals. Two field-studies conducted in Orlando, FL are used to investigate nitrogen and phosphorus removals when FTWs are deployed, and compared to the control counterparts without the FTWs. The first evaluation was performed in Pond 4M at The University of Central Florida (UCF). The data was used to create an estimated 12% nutrient removal credit presented in a report to the Florida Department of Transportation (FDOT).

Stormwater Treatment Evaluation of a Constructed Floating Wetland after Two Years Operation in an Urban Catchment

“…A comparison between the removal efficiencies presented in other studies on large-scale CFWs [5][6][7][8][9][10] and those revealed in this study is difficult due to the different treatment system designs, sampling procedures, and evaluation procedures used in the studies. This difficulty was also discussed by Headley & Tanner [21].…”

“…A literature review identified six previous studies [5][6][7][8][9][10] which investigated the removal of total suspended solids (TSS) and nutrients from stormwater ponds by CFWs at seven different locations. All of the stormwater ponds investigated had a surface area of 100 m 2 or larger.…”