Removal of anionic surfactants from wastewater using a constructed wetland.
Removal of anionic surfactants from municipal wastewater using a constructed wetland with a horizontal subsurface flow was studied in 2007 and 2008. Extraction spectrophotometry with methylene blue served to determine the analyte concentrations in individual samples. The anionic surfactant-removal efficiency depended on actual conditions, mostly the treated water flow intensity, its temperature, and a redox-potential gradient in the longitudinal profile of the wetland bed. It increased with decreasing inflow and increasing temperature. The average efficiency was 83.7% in 2007 and 81.7% in 2008; however, values higher than 85% were often determined during the summer period. On the other hand, the efficiencies were usually lower than 80% in winter, especially in periods with intensive precipitation and inflows. The average concentration of anionic surfactants in water taken at the outflow was lower than 0.65 mg/l (expressed as sodium dodecyl sulfate). The most significant fraction of anionic surfactants (almost 50%) was degraded at the beginning (1 m from the inflow zone) of the wetland bed. The rhizosphere aeration via the vegetation roots strongly supported the anionic-surfactant removal.
Síma
Jan
J
Institute of Chemistry and Biochemistry, University of South Bohemia, Faculty of Science, Branisovská 31, CZ-37005 Ceské Budejovice. sima@prf.jcu.cz
Havelka
Michal
M
Holcová
Veronika
V
D000383:Agriculture; D001673:Biodegradation, Environmental; D005456:Fluorescent Dyes / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*; D053833:Wetlands
D005456:Fluorescent Dyes; D013501:Surface-Active Agents