Removal of phenol, bisphenol A, and 4-tert-butylphenol from synthetic landfill leachate by vertical flow constructed wetlands.

Lab-scale vertical flow constructed wetlands (CWs) were used to remove phenol, bisphenol A (BPA), and 4-tert-butylphenol (4-t-BP) from synthetic young and old leachate. Removal percentages of phenolic compounds from the CWs were in the following order: phenol (88-100%)>4-t-BP (18-100%)≥BPA (9-99%). In all CWs, phenol was removed almost completely from leachate. Results show that BPA and 4-t-BP were removed more efficiently from CWs planted with Phragmites australis than from unplanted CWs, from old leachate containing lower amounts of acetate and propionate as easily degradable carbon sources than from young leachate, and in the dry season mode with long retention time than in the wet season mode with short retention time. Adsorption by initial removal and subsequent biodegradation processes might be major removal processes for these phenolic compounds. The presence of plant is beneficial for enrichment of BPA-degrading and 4-t-BP-degrading bacteria and for the carbon source utilization potential of microbes in CWs.