Removal of nonionic surfactants from municipal wastewater using a constructed wetland with a horizontal subsurface flow was studied in 2009 and 2010. Extraction spectrophotometry with 3',3″,5',5″-tetrabromophenolphthalein ethyl ester and KCl served to determine the analyte concentrations. Triton(®) X-100 was used as a standard to express the nonionic-surfactant concentrations. Anionic and cationic surfactants were shown not to interfere during the determination. Nonionic surfactants were degraded (to products undeterminable by the method) with a high average efficiency that reached 98.1% in 2009 and 99.1% in 2010, respectively. The average concentration of nonionic surfactants at the inflow was 0.978 mg/l, while it was close to the limit of quantification at the outflow (0.014 mg/l). A significant fraction of nonionic surfactants (38.7%) was already degraded during the pretreatment, and only 14.0% of the nonionic surfactants remained in the interstitial H(2) O taken in the vegetation bed at a distance of 1 m from the inflow zone at a 50-cm depth. Nonionic surfactants were degraded both under aerobic and anaerobic conditions.

Department of Ecosystem Biology University of South Bohemia Faculty of Science Branišovská 31 CZ 37005 České Budějovice

Institute of Chemistry and Biochemistry University of South Bohemia Faculty of Science Branišovská 31 CZ 37005 České Budějovice

References provided by Crossref.org