Abstract
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).