title: Seasonal performance of an outdoor constructed wetland for graywater treatment in a temperate climate.
abstract: The seasonal treatment efficiency of a pilot-scale constructed wetland system located outdoors in a semi-arid, temperate climate was evaluated for graywater in a comprehensive, 1-year study. The system consisted of two wetland beds in series--a free water surface bed followed by a subsurface flow bed. Water quality monitoring evaluated organics, solids, nutrients, microbials, and surfactants. The results showed that the wetland substantially reduced graywater constituents during fall, spring, and summer, including biochemical oxygen demand (BOD) (92%), total nitrogen (85%), total phosphorus (78%), total suspended solids (TSS) (73%), linear alkylbenzene sulfonate (LAS) surfactants (94%), and E. coli (1.7 orders of magnitude). Except for TSS, lower removals of graywater constituents were noted in winter--BOD (78%), total nitrogen (64%), total phosphorus (65%), LAS (87%), and E. coli (1.0 order), indicating that, although wetland treatment slowed during the winter, the system remained active, even when the average water temperature was 5.2 +/- 4.5 degrees C.
authors.affiliation: Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Jokerst
authors.forename: Sybil E
authors.initials: SE
authors.lastname: Sharvelle
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Hollowed
authors.forename: Larry A
authors.initials: LA
authors.lastname: Roesner
mesh_terms: D002980:Climate; D004926:Escherichia coli / Q000302:isolation & purification; D010865:Pilot Projects; D012621:Seasons; D014871:Water Microbiology; D014873:Water Pollutants / Q000302:isolation & purification*; D053833:Wetlands
chemical_list: D014873:Water Pollutants