Nutrient Removal with Passive Floating Treatment Wetlands

CASE STUDY: Elayn Hunt Correctional Facility
The Floating Islands technology is the most innovative cost—effective technology to come along in a long time. The technology has the potential to allow many communities and facilities to finally achieve compliance.`` Dr. Harold Leggett, former Secretary Louisiana Dept. of Environmental Quality
Municipal Wastewater Pond, Elayn Hunt Correctional Facility
Project Location: St. Gabriel, Louisiana, USA

This case study demonstrates the ability of patented BioHaven® floating treatment wetlands technology (FTW) to clean water by substantially reducing nutrient levels.  At wastewater facility in Louisiana, BioHavens® more than doubled removal rates for chemical oxygen demand (COD), ammonia, and phosphate.


Martin Ecosystems of Baton Rouge, Louisiana, a Floating Island International licensee, installed BioHaven® floating islands into the Elayn Hunt Correctional Facility oxidation pond in March 2011.  The primary objective was to determine whether the islands could remove unwanted nutrients that were periodically creating noncompliance with the facility’s discharge permit.  The goal is to have the facility continually achieve and maintain compliance.


Parameters Studied


FTW Size

Water Source

Installation Date

Flow Rate

Water Body Depth

Water Body Area

% Coverage

St. Gabriel, Louisiana, USA

COD, ammonia, phosphate

Municipal wastewater pond

Area of 1560 sq. ft. @ 8 inches thick

Elayn Hunt Correctional oxidation pond

March 2011

208 gpm

3 feet

5.1 acre

0.7% of pond covered by BioHavens®

The BioHavens® installed at Elayn Hunt are passive islands without aeration and were planted with three types of vegetation.  Most of the removal efficiency attributed to islands has been found to be due to biofilm attached to both the plant roots and the island matrix itself.

Table 1 shows concentrations of the three parameters of concern before and after BioHaven® installation.  “Before” data were taken in January and March 2011, while “after” data are the averages of monthly data from April 2011 through September 2012.  It is assumed that the higher nutrient concentrations seen post-FTW were also seen periodically before BioHaven® installation.

Table1 Hunt Correctional Facility Passive Islands


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