Transformation of diclofenac in hybrid biofilm-activated sludge processes.
The biotransformation of diclofenac during wastewater treatment was investigated. Attached growth biomass from a carrier-filled compartment of a hybrid-MBBR at the wastewater treatment plant (WWTP) in Bad Ragaz, Switzerland was used to test the biotransformation. Laboratory-scale incubation experiments were performed with diclofenac and carriers and high-resolution LC-QTof-MS was implemented to monitor the biotransformation. Up to 20 diclofenac transformation products (TPs) were detected. Tentative structures were proposed for 16 of the TPs after characterization by MS2fragmentation and/or inferring the structure from the transformation pathway and the molecular formula given by the high resolution ionic mass. The remaining four TPs were unambiguously identified via analytical reference standards. The postulated reactions forming the TPs were: hydroxylation, decarboxylation, oxidation, amide formation, ring-opening and reductive dechlorination. Incubation experiments of individual TPs, those which were available as reference standards, provided a deeper look into the transformation pathways. It was found that the transformation consists of four main pathways but no pathway accounted for a clear majority of the transformation. A 10-day monitoring campaign of the full-scale plant confirmed an 88% removal of diclofenac (from approximately 1.6 μg/L in WWTP influent) and the formation of TPs as found in the laboratory was observed. One of the TPs, N-(2,6-dichlorophenyl)-2-indolinone detected at concentrations of around 0.25 μg/L in WWTP effluent, accounting for 16% of the influent diclofenac concentration. The biotransformation of carriers was compared to a second WWTP not utilising carriers. It was found that in contact with activated sludge, similar hydroxylation and decarboxylation reactions occurred but at much slower rates, whereas some reactions, e.g. reductive dechlorination, were not detected at all. Finally, incubation experiments were performed with attached growth biomass from a third WWTP with a similar process configuration to Bad Ragaz WWTP. A similarly effective removal of diclofenac was found with a similar presence of TPs.
Federal Institute of Hydrology, Am Mainzer Tor 1, 56068, Koblenz, Germany.
Kevin S
KS
Jewell
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600, Dübendorf, Switzerland.
Per
P
Falås
Federal Institute of Hydrology, Am Mainzer Tor 1, 56068, Koblenz, Germany.
Arne
A
Wick
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600, Dübendorf, Switzerland.
Adriano
A
Joss
Federal Institute of Hydrology, Am Mainzer Tor 1, 56068, Koblenz, Germany. Electronic address: ternes@bafg.de.
Thomas A
TA
Ternes
D018441:Biofilms; D004008:Diclofenac; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
D004008:Diclofenac; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
Diclofenac; Moving-bed biofilm reactor; Transformation products; Wastewater treatment
Sci Total Environ. 2014 Mar 1;473-474:125-31
24365588
Xenobiotica. 1979 Oct;9(10):601-10
119352
Environ Sci Technol. 2014 Feb 18;48(4):2097-8
24476540
Aquat Toxicol. 2006 Feb 10;76(2):122-59
16257063
Water Res. 2005 Jul;39(12):2654-64
15979124
Chemosphere. 2008 Nov;73(8):1151-61
18793791
Environ Sci Technol. 2015 Dec 15;49(24):14282-91
26555603
Water Res. 2013 Sep 1;47(13):4498-506
23764599
Water Res. 2005 Apr;39(7):1289-300
15862328
Water Res. 2006 May;40(8):1686-96
16620900
Nature. 2004 Feb 12;427(6975):630-3
14745453
Drug Metab Dispos. 2001 Dec;29(12):1608-13
11717180
Environ Sci Technol. 2011 May 1;45(9):3835-47
21473617
Sci Total Environ. 2008 Nov 1;405(1-3):310-6
18640705
J Chromatogr A. 2010 Oct 15;1217(42):6511-21
20832069
Chemosphere. 2007 Sep;69(4):509-16
17524452
Sci Total Environ. 2014 Mar 1;473-474:619-41
24394371
Anal Chem. 2008 Nov 1;80(21):8135-45
18821734
Environ Sci Pollut Res Int. 2015 Apr;22(8):5864-76
25352396
Sci Total Environ. 2012 Jul 1;429:123-55
22583809
Chemosphere. 2012 May;87(8):969-74
22401746
Water Res. 2014 Nov 15;65:371-83
25150522
Water Res. 2011 May;45(11):3417-26
21536314
J Chromatogr A. 2015 Dec 24;1426:77-90
26654253
Environ Int. 2014 Aug;69:28-39
24791707
Aquat Toxicol. 2004 Jun 10;68(2):151-66
15145225
Water Res. 2015 Oct 15;83:293-302
26164801
Environ Pollut. 2014 Oct;193:29-36
24997388
J Hazard Mater. 2009 Nov 15;171(1-3):1051-7
19615816
Ultrason Sonochem. 2013 Jul;20(4):1104-12
23352585
Appl Microbiol Biotechnol. 2005 Jun;67(5):600-18
15672270
Gastroenterology. 1998 Dec;115(6):1476-82
9834275
Environ Sci Pollut Res Int. 2013 Jun;20(6):3592-606
23532532
Appl Environ Microbiol. 1997 Mar;63(3):973-7
16535560
Xenobiotica. 2012 Feb;42(2):179-94
21955289