TITLE:
Sludge Removal of Nonsteroidal Anti-Inflammatory Drugs during Wastewater Treatment Studied by Direct Hollow Fiber Liquid Phase Microextraction
AUTHORS:
Estelle Larsson, Ayman Rabayah, Jan Åke Jönsson
KEYWORDS:
Pharmaceuticals; Sewage Sludge; HF-LPME; NSAID; Extraction; WWTP; Analysis
JOURNAL NAME:
Journal of Environmental Protection,
Vol.4 No.9,
August
29,
2013
ABSTRACT:
In this study, the fate of
four common anti-inflammatory drugs (ketoprofen, naproxen, diclofenac and ibuprofen)
within a wastewater treatment plant was investigated. A previously developed
direct hollow fiber liquid phase microextraction method was applied to water as
well as sludge samples collected from the primary, secondary and tertiary
treatment respectively and the final analysis was performed by liquid
chromatography quadropole time of flight tandem mass spectrometry. Enrichment
factors ranged from 1400 to 3900 times depending on analyte and matrix. Method
detection limits ranged from 0.3 to 14 ng/L for the different analytes and
matrices. The overall sludge removal was 9%, 3%, 13% and 1% for ketoprofen,
naproxen, diclofenac and ibuprofen respectively, thus indicating that of the
studied compounds, ketoprofen and diclofenac to the largest extent partition
into the sludge. For both substances, the largest fraction was found in secondary sludge (60% and 80%
respectively of the total amount detected in the sludge). For naproxen and
ibuprofen, the largest fraction were on the other hand detected in primary and
tertiary sludge respectively, indicating that the affinity to the different
sludge types might vary among the four drugs. The overall low sludge removal confirms
existing theories that partitioning into sludge is only a minor removal
mechanism for the investigated compounds. Nevertheless, naproxen and ibuprofen are still efficiently removed from the
water during treatment (100% and 97 % total removal respectively) suggesting that these compounds are
highly susceptible to biodegradation while ketoprofen and diclofenac (66% and
67% total removal respectively) appear more persistent.