Removal of floodwater nitrogen in a cypress swamp receiving primary wastewater effluent

• Published in: Hydrobiologia 1987-10, Vol.153 (1), p.79-86
• Main Authors: DEBUSK, W. F, REDDY, K. R
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biological treatment of waters; Biotechnology; Brackish; Environment and pollution; Freshwater; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/BF00005506

Triplicate cores were obtained from 3 sites in a flowing Florida cypress swamp: the upper region, subjected to 50 years of wastewater application; an experimental enclosure, into which wastewater had been pumped for 2 years; and an undisturbed area receiving an initial application. Ammonia-nitrogen tagged with nitrogen-15 was used to identify the processes involved in removal of floodwater ammonium-nitrogen and to evaluate the effect of long-term wastewater application on nitrogen-removal efficiency. The rate of inorganic-nitrogen decrease in the floodwater was greatest for the initial application cores, due to sediment absorption of ammonium, followed by the 2-year and 50-year columns. At the end of the 21 day experimental period, 0.5-2.3 per cent nitrogen-15 was recovered in floodwater, 11.4-17.3 per cent recovered in the sediment, the remaining 82.2-86.3 per cent being lost from the sediment-water system. It was concluded that the nitrogen removal capability of the forested wetland did not decrease over time, despite greatly increased levels of ammonium in the sediment, because of significant gaseous nitrogen losses.