|GASCHO, GARY - U. OF GEORGIA
|NEWTON, G. - U. OF GEORGIA
Submitted to: The Southern Agriculture Workers Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/8/2003
Publication Date: 10/20/2003
Citation: HUBBARD, R.K., GASCHO, G.J., NEWTON, G.L. USE OF FLOATING VEGETATION TO REMOVE NUTRIENTS FROM SWINE WASTEWATER LAGOONS. THE SOUTHERN AGRICULTURE WORKERS MEETING. ABSTRACT P. 26. 2003.
Technical Abstract: Methods are needed to remove nutrients from wastewater lagoons. Most removal methods involve land application of the wastewater with nutrient removal by vegetation or losses through such processes as NH4 volatilization or denitrification. However, potential exists for nutrient removal directly from the lagoons if vegetation can be grown in them and periodically removed. Vegetative cover of lagoons may also help reduce odor problems. A study was conducted to investigate the feasibility of using floating mats of vegetation on swine wastewater lagoons. Wastewater from the University of Georgia swine wastewater lagoons was pumped to replicated tanks (1285 L) in which floating mats of vegetation were grown. The floating platforms were made of PVC pipe with attached wire screen and fibrous material into which the vegetation was sprigged. Three different wetland species were tested; maidencane (Panicum hematomon Schult >Halifax=), cattail (Typha angustifolia L.), and soft rush (Juncus effusus L.). Full strength wastewater, 1/2 strength wastewater, and an inorganic nutrient solution (1/4 strength Hoaglund solution) as a control were tested. There were 4 replicate tanks of each nutrient solution for each wetland species for a total of 36 tanks. Vegetation from the floating mats was harvested periodically by removing all vegetation above 5 cm from the base of the floating mat. Measurements were made at each cutting of the total biomass per tank, leaf area (using a Li-Cor leaf area meter) and nutrient content (N,P,K) of the vegetative tissue. Growth responses were quite different between the three species. The cattail had tremendous growth during the summer months but went dormant during the winter. The growth rate of the rush was slow but it did not go dormant during the winter months. Total nutrient removal was primarily a function of total biomass produced. Results from the study indicated that potential exists for using floating platforms to grow wetland plants in wastewater lagoons for nutrient removal.