AMMONIA VOLATILIZATION FROM CONSTRUCTED WETLANDS THAT TREAT SWINE WASTEWATER

摘要

Increasingly, large-scale animal production occurs in confinement where large per-unit-area quantities of waste are generated. With the increased scale of production, new environment-friendly technologies are needed to deal with the waste. Constructed wetlands are considered an alternative treatment, but it is not known if volatilization of free ammonia (NH ₃ ) governs nitrogen removal in these systems. The objective of this research was to quantify the NH ₃ volatilization from constructed wetlands that treat swine wastewater. In May and July of 2000, a specially designed enclosure was used to measure NH ₃ volatilization from constructed wetlands receiving swine wastewater. Laboratory and field calibration tests indicated that the enclosure was effective at measuring NH ₃ volatilization. Wetland tests indicated that NH ₃ volatilization was occurring. From average hourly rates, it was estimated that 7% to 16% of the nitrogen load to the wetlands was removed through NH ₃ volatilization. Although NH ₃ losses should not be ignored, results indicated that NH ₃ volatilization was not responsible for removing the majority of nitrogen from the swine wastewater