title: Nitrification cessation and recovery in an aerated saturated vertical subsurface flow treatment wetland: Field studies and microscale biofilm modeling.
abstract: In aerated treatment wetlands, oxygen availability is not a limiting factor in sustaining a high level of nitrification in wastewater treatment. In the case of an air blower failure, nitrification would cease, potentially causing adverse effects to the nitrifying bacteria. A field trial was completed investigating nitrification loss when aeration is switched off, and the system recovery rate after the aeration is switched back on. Loss of dissolved oxygen was observed to be more rapid than loss of nitrification. Nitrate was observed in the effluent long after the aeration was switched off (48h+). A complementary modeling study predicted nitrate diffusion out of biofilm over a 48h period. After two weeks of no aeration in the established system, nitrification recovered within two days, whereas nitrification establishment in a new system was previously observed to require 20-45days. These results suggest that once established resident nitrifying microbial communities are quite robust.
authors.affiliation: ARM Ltd, Rugeley, Staffordshire, UK.
authors.forename: Clodagh
authors.initials: C
authors.lastname: Murphy
authors.affiliation: School of Engineering Technology, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Amin R
authors.initials: AR
authors.lastname: Rajabzadeh
authors.affiliation: Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario, Canada. Electronic address: kela.weber@rmc.ca.
authors.forename: Kela P
authors.initials: KP
authors.lastname: Weber
authors.affiliation: Helmholtz Center for Environmental Research (UFZ), Environmental and Biotechnology Center (UBZ), Leipzig, Germany.
authors.forename: Jaime
authors.initials: J
authors.lastname: Nivala
authors.affiliation: Naturally Wallace Consulting LLC, Raleigh, NC, USA.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Wallace
authors.affiliation: ARM Ltd, Rugeley, Staffordshire, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Cooper
mesh_terms: D000388:Air; D018441:Biofilms; D004867:Equipment Design; D008962:Models, Theoretical; D009566:Nitrates / Q000378:metabolism; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism; D010100:Oxygen / Q000032:analysis / Q000378:metabolism; D013997:Time Factors; D006113:United Kingdom; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater; D018508:Water Purification / Q000379:methods; D053833:Wetlands
chemical_list: D009566:Nitrates; D009584:Nitrogen; D010100:Oxygen; D062065:Wastewater
keywords: Aeration; Constructed wetland; Denitrification; Diffusion; Intensified wetland