Partition and fate analysis of fluoroquinolones in sewage sludge during anaerobic digestion with thermal hydrolysis pretreatment

•A SPE with HPLC-FLD method was successfully applied for analysis of FQs in sludge.•Thermal hydrolysis did not remove FQs but increased their distribution in liquid.•Anaerobic digestion alone removed > 60% of FQs.•The inhibitory effects of FQs to microbial community was mitigated.•The individual FQ differs greatly in their fate and distribution.

Fluoroquinolones (FQs) are broad-spectrum synthetic antibiotics that play an important role in the treatment of serious bacterial infections. FQs can reach wastewater treatment plants from different routes, and eventually accumulate in activated sludge. In this study, a solid-phase extraction (SPE) with HPLC-FLD detection method was utilized to investigate the partition and fate of FQs in digested sludge when thermal hydrolysis was used as pretreatment. As a result, thermal hydrolysis showed minor effects on the fate of FQs in batch anaerobic digestion processes, while anaerobic digestion alone removed > 60% FQs and finally assisted in the mitigation of the inhibitory effects to microbial communities.

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