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Title: Synergistic ammonia losses from animal wastewater

Author
item Lee, Sang
item Yates, Scott
item ROBARGE, WAYNE - North Carolina State University
item WALKER, JOHN - Environmental Protection Agency (EPA)
item Bradford, Scott

Submitted to: Atmospheric Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/24/2013
Publication Date: 6/1/2013
Citation: Lee, S.R., Yates, S.R., Robarge, W.P., Walker, J.T., Bradford, S.A. 2013. Synergistic ammonia losses from animal wastewater. Atmospheric Environment. 17:245-250.

Interpretive Summary: Animal feeding operations (AFOs) are estimated to account for 71% of the ammonia emissions in the United States. Atmospheric deposition of ammonia can contribute to eutrophication of surface waters, over-fertilization of crops, and soil acidification. Furthermore, ammonia emissions from AFOs is also a significant source for atmospheric fine particular matter (PM2.5) and health studies indicate that exposure of individuals to PM2.5 is associated with increased risks of respiratory and cardiovascular problems. Understanding of factors that influence ammonia emissions from AFOs is therefore essential for ecosystem and human health. In this study, a thin-film mass transfer model is used to estimate ammonia emissions from pure solution and liquid animal wastes. Experiments were conducted to measure the concentration of total ammonia nitrogen (TAN) in solution under controlled pH and temperature conditions. The effect of TAN concentration and additions of bicarbonate on ammonia emissions were studied for pure solution and AFO wastewater. The results show that increasing TAN or bicarbonate increases ammonia emissions in a predictable manner. Understanding these relationships will help scientists, regulators and animal producers to reduce nuisances and human and environmental risks associated with AFO ammonia emissions.

Technical Abstract: Thin-layer models are commonly used to estimate ammonia emissions from liquid waste. However, such models differ in their ability to accurately reproduce observed emissions, which may be partly due to an incomplete mechanistic understanding of ammonia volatilization. In this study, ammonia release from pure solutions of ammonium sulfate (AS), swine pit liquid (PL), swine lagoon liquid (LL), dairy lagoon liquid (DLL), and dairy manure liquid (DML) were evaluated under controlled conditions (pH 7.6 and temperature 20C). Relationships between the ammonia release and pH, temperature, and total ammoniacal nitrogen (TAN) were established. Under similar TAN conditions, the ammonia release was higher for PL, LL, DLL, and DML than for AS. Pure solutions of AS that were spiked with sodium bicarbonate showed ammonia emissions rates that were comparable to DML and PL. The enhanced ammonia emissions of PL, LL, DLL and DML were therefore explained by linkages between TAN and bicarbonate.