Occurrence and reduction of pharmaceuticals in the water
phase at Swedish wastewater treatment plants
P. Falås, H. R. Andersen, A. Ledin and J. la Cour Jansen
ABSTRACT
During the last decade, several screening programs for pharmaceuticals at Swedish wastewater
treatment plants (WWTPs) have been conducted by research institutes, county councils, and
wastewater treatment companies. In this study, influent and effluent concentrations compiled from
these screening programs were used to assess the occurrence and reduction of non-antibiotic
pharmaceuticals for human usage. The study is limited to full-scale WWTPs with biological treatment.
Based on the data compiled, a total of 70 non-antibiotic pharmaceuticals have been detected, at
concentrations ranging from a few ng/L to several μg/L, in the influent water. The influent
concentrations were compared with the sale volumes and for many pharmaceuticals it was shown
that only a small fraction of the amount sold reaches WWTPs as dissolved parent compounds.
Pharmaceuticals with low reduction degrees at traditional WWTPs were identified. Further
comparison based on the biological treatment showed lower reduction degrees for several
pharmaceuticals in trickling filter plants compared with activated sludge plants with nitrogen removal.
P. Falås (corresponding author)
A. Ledin
J. la Cour Jansen
Water and Environmental Engineering,
Department of Chemical Engineering,
Lund University,
P.O. Box 124,
SE-221 00 Lund,
Sweden
E-mail: Per.Falas@chemeng.lth.se
H. R. Andersen
Department of Environmental Engineering,
Technical University of Denmark,
B113 DK-2800 Kgs Lyngby,
Denmark
Key words | biological treatment, pharmaceuticals, wastewater treatment
INTRODUCTION
Continuous discharge of pharmaceuticals with treated
wastewater may present a threat to the aquatic environment.
Removal efficiency of these substances at wastewater treat-
ment plants (WWTPs) is often highly dependent on the
biological treatment step (Carballa et al. ; Zorita et al.
); moreover, there is an indication that the biological
treatment design can influence the overall removal of estro-
genic activity (Kirk et al. ; Svenson et al. ) and
pharmaceuticals (Kasprzyk-Hordern et al. ).
The importance of solid retention time (SRT) to pharma-
ceutical removal in biological systems with suspended
bacteria cultures is widely discussed (Strenn et al. ;
Clara et al. a; Kimura et al. ). Furthermore, Clara
et al.(b) observed a critical SRT, above which signifi-
cant removal of several micropollutants can be achieved,
of approximately 10 d at a reference temperature of 10
W
C.
The critical SRT coincides with the SRT required for nitrifi-
cation, which is essential for plants with extended biological
nitrogen removal. This observation is particularly important
for Sweden as the extended nitrogen removal in Sweden
depends on plant location and size.
Identification of wastewater effluents as a main source
of pharmaceuticals to the aquatic environment has led to
extensive pharmaceutical sampling at Swedish WWTPs
over the past decade (Paxéus , ; Andersson et al.
; Helmfrid ; Region Skåne ; Woldegiorgis
et al. ; Helmfrid & Eriksson ). This sampling has
been initiated by a wide range of organisations including
research institutes, county councils, and wastewater treat-
ment companies. Some results have been published
internationally while others have been presented in Sweden
or kept within the organisations. When looked at as a
whole, the results from these sampling campaigns offer a
unique opportunity to investigate the occurrence and
reduction of pharmaceuticals in WWTPs at a national level.
Most overviews of pharmaceutical removal at WWTPs
have been based on international literature data (Buntner
et al. ; Miège et al. ). National WWTP design cri-
teria, which are influenced by discharge requirements,
climate, and treatment history, may cause differences in
pharmaceutical removal between countries. The pharma-
ceutical concentrations in untreated wastewater may also
vary between countries due to national differences in
pharmaceutical consumption and wastewater production.
This study has three aims and is based on data from the
extensive sampling of pharmaceuticals at Swedish WWTPs,
783 © IWA Publishing 2012 Water Science & Technology | 66.4 | 2012
doi: 10.2166/wst.2012.243