Upgrading of Wastewater Treatment Plants Through the Use of Unconventional Treatment Technologies: Removal of Lidocaine, Tramadol, Venlafaxine and Their Metabolites

摘要

The occurrence and removal efficiencies of the pharmaceuticals lidocaine (LDC), tramadol (TRA) and venlafaxine (VEN), and their major active metabolites monoethylglycinexylidide (MEGX), O-desmethyltramadol (ODT) and O-desmethylvenlafaxine (ODV) were studied at four wastewater treatment plants (WWTPs) equipped with activated sludge treatment technologies. In parallel to activated sludge treatment, the removal efficiency of the compounds in pilot- and full-scale projects installed at the WWTPs was investigated. Within these projects two different treatment methods were tested: adsorption onto powdered/granulated activated carbon (PAC/GAC) and ozonation. The metabolite MEGX was not detected in any sample. The concentrations of the target analytes in wastewater effluents resulting from activated sludge treatment ranged from 55 to 183 (LDC), 88 to 416 (TRA), 50 to 245 (ODT), 22 to 176 (VEN) and 77 to 520 ng L−1 (ODV). In the pilot project with subsequent treatment with PAC/GAC, the mean concentrations of the analytes were between LOQs and 30 (LDC), 111 (TRA), 140 (ODT), 45 (VEN) and 270 ng L−1 (ODV). In the pilot project with subsequent ozonation of the effluent from the conventional treatment the mean concentrations were below the limit of quantification (LOQ) for all of the investigated compounds. The results showed limitations of activated sludge treatment technologies in removing the target compounds but highlighted both PAC/GAC adsorption and ozonation technologies as effective post-treatment processes for the elimination of the target compounds from wastewater in WWTPs. Possible oxidation by-products formed during ozonation were not analyzed.