Sludge Removal of Nonsteroidal Anti-Inflammatory Drugs during Wastewater Treatment Studied by Direct Hollow Fiber Liquid Phase Microextraction

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 liq. phase microextn. method was applied to water as well as sludge samples collected from the primary, secondary and tertiary treatment resp. and the final anal. was performed by liq. chromatog. 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 matrixes. The overall sludge removal was 9%, 3%, 13% and 1% for ketoprofen, naproxen, diclofenac and ibuprofen resp., thus indicating that of the studied compds., 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% resp. of the total amt. detected in the sludge). For naproxen and ibuprofen, the largest fraction were on the other hand detected in primary and tertiary sludge resp., 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 compds. Nevertheless, naproxen and ibuprofen are still efficiently removed from the water during treatment (100% and 97% total removal resp.) suggesting that these compds. are highly susceptible to biodegrdn. while ketoprofen and diclofenac (66% and 67% total removal resp.) appear more persistent. [on SciFinder(R)]