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Nitrogen Removal from Wastewater by an Aerated Subsurface‐Flow Constructed Wetland in Cold Climates
Author(s) -
Redmond Eric D.,
Just Craig L.,
Parkin Gene F.
Publication year - 2014
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143013x13736496908591
Subject(s) - aeration , effluent , nitrogen , chemical oxygen demand , ammonia , wastewater , environmental chemistry , wetland , chemistry , environmental engineering , constructed wetland , biochemical oxygen demand , pulp and paper industry , environmental science , ecology , biology , biochemistry , organic chemistry , engineering
The objective of this study was to assess the role of cyclic aeration, vegetation, and temperature on nitrogen removal by subsurface‐flow engineered wetlands. Aeration was shown to enhance total nitrogen and ammonia removal and to enhance removal of carbonaceous biochemical oxygen demand, chemical oxygen demand, and phosphorus. Effluent ammonia and total nitrogen concentrations were significantly lower in aerated wetland cells when compared with unaerated cells. There was no significant difference in nitrogen removal between planted and unplanted cells. Effluent total nitrogen concentrations ranged from 9 to 12 mg N/L in the aerated cells and from 23 to 24 mg N/L in unaerated cells. Effluent ammonia concentrations ranged from 3 to 7 mg N/L in aerated wetland cells and from 22 to 23 mg N/L in unaerated cells. For the conditions tested, temperature had only a minimal effect on effluent ammonia or total nitrogen concentrations. The tanks‐in‐series and the PkC * models predicted the general trends in effluent ammonia and total nitrogen concentrations, but did not do well predicting short‐term variability. Rate coefficients for aerated systems were 2 to 10 times greater than those for unaerated systems.