Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/26/1997
Publication Date: N/A
Technical Abstract: Constructed wetlands can remove large amounts of N from swine wastewater (approx. 2,600 kg/ha/yr). However, conversion of ammonia to nitrate (nitrification) appears to be the limiting factor for maximum N removal by wetlands. A microcosm wetland study was established in 1996 to assess the possibility of sequencing nitrification-wetland treatments. Wastewater enriched with nitrate was applied to the microcosm wetland units at a rate of 190 kg nitrate/ha and a retention time of four days. Results showed that wetland treatments removed 80% of the total nitrate applied compared to 14% removal by a control treatment with no plants. This removal potential is equivalent, on an annual basis, to about 14,000 kg N/ha, which is 5.4 times higher than the N removal without nitrification pretreatment. This indicates that the capacity of mass N removal by wetlands can be significantly increased by nitrification pretreatment.