Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2002
Publication Date: 6/1/2002
Citation: STONE, K.C., HUNT, P.G., SZOGI, A.A., HUMENIK, F.J., RICE, J.M. CONSTRUCTED WETLAND DESIGN AND PERFORMANCE FOR SWINE LAGOON WASTEWATER TREATMENT. TRANSACTIONS OF THE AMERICAN SOCIETY OF AGRICULTURAL ENGINEERS. 2002. V. 45. P. 723-730. Interpretive Summary: Protecting the quality our nation's streams and ground water is a national concern. This concern is especially critical in environmentally sensitive areas such as the eastern Coastal Plain of the US. In the eastern Coastal Plain and during the past decade, there has been a large increase in animal production. This increase in animal production has led to additional environmental concerns because of the large amount of waste produced by these animal production facilities. These animal wastes must be treated in an environmentally sustainable manner. Traditional treatment methods need to be enhanced or replaced to prevent adverse impacts on the surrounding streams and ground water. One alternative to enhance treatment is the use of constructed wetlands. Constructed wetlands have been used for many years in municipal wastewater treatment. We built a constructed wetland in 1992 to treat swine lagoon effluent. We evaluated how well the constructed wetland treated the swine lagoon effluent from 1993 to 1999. We found that the constructed wetlands were very effective in treating nitrogen. Using these results, we calculated some equations and parameters that engineers and consultants can use in the construction and design of future systems.
Technical Abstract: Constructed wetlands have been identified as a potentially important component for treatment of animal wastewater. They have been used for many years in municipal wastewater treatment. The technical requirements were based mainly on municipal systems and limited data on animal waste systems. The majority of constructed wetlands for treatment of animal waste have been installed since 1989. Constructed wetlands to treat swine lagoon effluent were installed in 1992 in Duplin County, NC. The constructed wetland performance data were analyzed to calculate design parameters that could be used in future constructed wetland design. The constructed wetlands were effective in treating nitrogen with a mean total nitrogen and ammonia-N concentration reduction efficiency of approximately 85%. The constructed wetlands were not effective for treating phosphorus with mean TP concentration reduction efficiency of 25 to 38%. Regression analyses to predict outflow concentration from inflow concentration and hydraulic loading rate were in close agreement with those in literature. These equations should be appropriate for use in estimating wetland treatment of nutrients within the observed range of nutrient loading rates. First-order equation treatment rate constants were much lower than those reported in literature and recommended for use in design of constructed wetland design. Use of our calculated rate constant and parameters would result in a more conservative design.