Swine Lagoon Wastewater Treatment in Marsh- Pond/Floating Wetland-Marsh Constructed Wetland

Constructed wetlands have been used effectively to reduce the mass loads of organic and nutrient components from swine anaerobic lagoons. Continuous marsh wetlands with gentle slope and intermittent flows seem to be the best for promoting oxidation and minimizing ammonia volatilization. However, the pond section of the marsh-pond-marsh section could potentially be effectively aerated by mechanical means or plant root transport from selected wetland plants. The objective of this research was to determine if covering the pond section with floating wetland vegetation could enhance nitrogen cycling, reduce ammonia volatilization, and lower estrogenic levels. Marsh-pond-marsh wetlands were retrofitted with a floating fabric cover containing slots for wetland plant establishment. Both mechanically aerated and naturally aerated conditions were evaluated for estrogenic component removals, ammonia volatilization, and total nutrient removals. Both the covered and uncovered wetlands reduced the estrogenic levels in the swine wastewater. The floating marsh substantially reduced the ammonia volatilization, but it did not promote significantly greater nitrogen treatment than reported for continuous marsh wetlands.