Periphyton contribution to nitrogen dynamics in the discharge from a wastewater treatment plant
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wastewater treatment plant
To evaluate the importance of periphyton to nitrogen dynamics in the discharge from wastewater treatment plants (WWTPs), we examined changes in total and inorganic nitrogen content downstream from a WWTP on the Kurose River in Hiroshima Prefecture, Japan. At 0.7 km downstream of the WWTP (point A), NH4+-N was the dominant form of inorganic nitrogen, but concentrations decreased rapidly to 5 km downstream (point B). In contrast, no significant change in the [NO2– + NO3–]-N concentration was observed between the two points. Total nitrogen (TN) load decreased significantly between the two points, suggesting that sorption and/or denitrification occurred in the river channel. Potential rates of nitrogen sorption and transformation by periphyton were determined in a laboratory experiment in which changes in the nitrogen content of river water were examined in an acrylic chamber with periphyton. Nitrification and nitrogen removal occurred mainly in the periphyton. The contributions of periphyton activity to TN and NH4+-N decrease in the field, as estimated from the results of the laboratory experiments, were 6%–18% and 23%–72%, respectively. These results suggest that periphyton plays an important role in decreasing NH4+-N concentration in the discharge from wastewater treatment plants.
River Research and Applications
John Wiley & Sons
(c) 2008 John Wiley & Sons, Ltd.
This is the peer reviewed version of the following article: "Periphyton contribution to nitrogen dynamics in the discharge from a wastewater treatment plant", which has been published in final form at http://doi.org/10.1002/rra.1186 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.