|Testa Iii, Sam|
Submitted to: Agricultural Research Service Publication
Publication Type: Other
Publication Acceptance Date: 1/20/1996
Publication Date: N/A
Interpretive Summary: Concentrated animal wastes from livestock create waste management problems that must be managed by individual farmers. New cost-effective methods are needed; thus, new treatment concepts are a priority of the Natural Resources Conservation Service and the Agricultural Research Service. A three year on-farm study evaluated the ability of a constructed wetland planted in bulrushes to process and trap different components of dairy cattle waste. Results showed that more specific guidelines for specific waste need to be worked out, but constructed wetlands show promise as efficient, cost-effective waste treatments that are low maintenance. This technology is of immediate interest to individual farmers, state and federal farm planners and industry.
Technical Abstract: The beneficial role of wetland ecosystems for improving water quality has been thoroughly documented. Recent research interests have begun to focus on applied uses of natural and constructed wetlands in the area of waste processing. Processing and disposing of concentrated on-farm animal waste, a major water quality concern,is a primary focus of the Natural Resources Conservation Service and regulatory agencies. A constructed wetland for treatment of dairy wastewater was built in DeSoto County, MS during 1990 by the Natural Resources Conservation Service and the Agricultural Research Service. Three parallel wetland cells, planted with giant bulrush, (*Scirpus validus*), were monitored for eighteen parameters for 3 years. Measures of physical and chemical water quality, BOD, and coliform bacteria were recorded, and average seasonal nutrient-trapping efficiencies were calculated. Total phosphorus reduction ranged from 28% to 87%, and ammonia was reduced 57% to 96% by treatment. Nitrate trapping varied from -278% to 87%; negative efficiency was due to conversion of ammonia to nitrate. Biological oxygen demand decreased more than 70%. Accumulation of senescent plant biomass in the treatment cells after two growing seasons caused reduced growth of bulrushes in some areas, suggesting a biomass removal strategy be implemented to maintain the culture. Constructed wetlands have considerable potential as cost- effective on-farm waste management systems. Further research is needed to evaluate their long-term effectiveness and range of applicability.