title: Nitrous oxide emissions from high rate algal ponds treating domestic wastewater.
abstract: This study investigated the generation of N2O by microcosms withdrawn from 7-L high rate algal ponds (HRAPs) inoculated with Chlorella vulgaris and treating synthetic wastewater. Although HRAPs microcosms demonstrated the ability to generate algal-mediated N2O when nitrite was externally supplied under darkness in batch assays, negligible N2O emissions rates were consistently recorded in the absence of nitrite during 3.5-month monitoring under 'normal' operation. Thereafter, HRAP A and HRAP B were overloaded with nitrate and ammonium, respectively, in an attempt to stimulate N2O emissions via nitrite in situ accumulation. Significant N2O production (up to 5685±363 nmol N2O/g TSS h) was only recorded from HRAP B microcosms externally supplied with nitrite in darkness. Although confirmation under full-scale outdoors conditions is needed, this study provides the first evidence that the ability of microalgae to synthesize N2O does not affect the environmental performance of wastewater treatment in HRAPs.
authors.affiliation: School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North, New Zealand; Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Alcántara
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Valladolid University, Dr. Mergelina, s/n, 47011 Valladolid, Spain. Electronic address: mutora@iq.uva.es.
authors.forename: Raúl
authors.initials: R
authors.lastname: Muñoz
authors.affiliation: School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North, New Zealand.
authors.forename: Zane
authors.initials: Z
authors.lastname: Norvill
authors.affiliation: School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North, New Zealand.
authors.forename: Maxence
authors.initials: M
authors.lastname: Plouviez
authors.affiliation: School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North, New Zealand.
authors.forename: Benoit
authors.initials: B
authors.lastname: Guieysse
mesh_terms: D053858:Metabolic Networks and Pathways; D058086:Microalgae / Q000378:metabolism*; D009609:Nitrous Oxide / Q000032:analysis*; D061005:Ponds / Q000737:chemistry*; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D009609:Nitrous Oxide; D062065:Wastewater
keywords: Algal pond; Chlorella vulgaris; Climate change; Nitrous oxide; Wastewater treatment performance