Phyto-Remediation of Nutrient Run-off From Recirculating Aquaculture System Using Lotus (Nelumbo nucifera Gaertn.)

Tuesday, September 27, 2011: 2:45 PM
Kings 1
Warner Orozco Obando , Flrec, University of Florida, Davie, FL
Floyd M. Woods , Auburn University, Auburn, AL
Ken Tilt , Auburn University, Auburn, AL
Edward van Santen, Ph., D. , Agronomy, Auburn University, Auburn, AL
Raymond Kessler Jr. , Department of Horticulture, Auburn University, Auburn, AL
Jesse Chappell , Horticulture, Auburn University, Auburn, AL
Fenny Dane , Auburn University, Auburn, AL
Jeff L. Sibley , Auburn University, Auburn University, AL
Jeremy Pickens , Horticulture, Auburn University, Auburn, AL
Wheeler Foshee , Auburn University, Auburn, AL
David Cline , Horticulture, Auburn University, Auburn, AL
John Olive , Horticulture, Auburn University, Auburn, AL
Deacue Fields , Agricultural Economics and Rural Sociology, Auburn University, Auburn, AL
Arnold W. Caylor , North Alabama Horticulture Research Center, Cullman, AL
Yiman Liu , Aquatic Vegetable Division, Wuhan Aquatic Vegetable Institute, Wuhan, Hubein, China
Guy-vanie Miakonkana , Horticulture, Auburn University, Auburn, AL
Xu Wang , Horticulture, Auburn University, Auburn, AL
Rucha Shewade , Horticulture, Auburn University, Auburn, AL
Constructed Wetlands (CWs) have been used effectively to remove nutrients, sediments, and pesticide residues from nursery run-off, sewage, and intense aquaculture systems. Traditionally, a limited variety of grasses and semi-aquatic plants have been used in CWs. Most of these plant species have low commercial/ornamental value and the land used to build the CWs is lost to production.  Lotus (Nelumbo nucifera) is an aquatic herbaceous perennial, sturdy, easy to grow, and with high biomass capacity.  In this study, remediation potential was determined by retaining fish effluents 24, 48 and 72 hours (Hydraulic Retention Time – HRT) in simulated Constructed Wetlands growing lotus (vegetated or V) and CWs without plants (V Non- vegetated or NV).  Multiple comparisons showed significant NH4+ removal from planted CWs with lotus and also influenced by HRT. There was a reduction in nitrate content of treated effluents but no differences were recorded when comparing vegetated vs. non-vegetated CWs. Potassium concentrations were reduced by V and HRT. Although, phosphorous removal varied between the two V and NV, they were effective on reducing P concentrations (p<0.0001). Although there were differences between treatments (HRT), reductions were higher on vegetated CWs after 48 and 72 h retention time. Data predicts reduced P as HRT increases.  Water pH was higher in all outflows from the CWs units when compared with control fish effluents. Initial pH (6.1) increased 15.3 - 16.4 % in the first 24 h. Suspended solids concentration was greatly reduced in the presence of plants and increased with HRT.  This study determined that fish water waste has the potential to provide an excellent source of nutrients for lotus plant growth yielding healthy, robust plants in CWs.  Lotus growing in CWs can substantially reduce the nutrient run-off from intense aquaculture systems.
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