|Humenik, Frank - NC STATE UNIV.|
Submitted to: International Conference on Wetland Systems for Water Pollution Control
Publication Type: Abstract Only
Publication Acceptance Date: October 15, 2000
Publication Date: N/A
Technical Abstract: Constructed wetlands are proposed as an alternative treatment technology for animal wastewater because they have been shown to be highly effective at nitrogen removal. Ammonia volatilization is not considered a problem in these constructed wetlands, but that has never been quantitatively verified. The objective of this research was to quantify ammonia that volatilized from wetlands constructed to treat swine wastewater. Our steady-state enclosure consisted of inlet and outlet flow-conditioning sections and a tunnel-shaped working section, which covers the experimental plot. The working section (4 m L x 1 m W x 2.5 m H) was sized to span the wetland cell and to enclose the wetland plants. Two variable-speed fans generated the airflow. A standard technique, gas washing bottles, and an innovative technique were used to measure ammonia. For the latter, ammonia was stripped from the outflow air by an acid solution circulating through an evaporative cooling pad. The efficiencies of the recovery systems were determined by volatilizing a known amount of ammonia in the enclosure. Recovery systems placed at the inlet of the enclosure determined background ammonia. Preliminary field tests in November and December of 1999 suggested that some ammonia was volatilizing from wetlands constructed to treat swine wastewater.