Effect of acclimation and nutrient supply on 5-tolyltriazole biodegradation with activated sludge communities

•5-Tolyltriazole biodegradation significantly improved by biomass acclimation.•Biodegradation enhancement by non-specific sludge supernatant addition.•Nitrogen addition also increased biodegradation rate.•Degradation presumably starts by benzene ring cleavage serving as a carbon source.•Heterocyclic N-containing ring is assumed not to be cleaved necessitating N-supply.

The corrosion inhibitor 5-tolyltriazole (5-TTri) can have a detrimental impact on aquatic systems thus implying an acute need to reduce the effluent concentrations of 5-TTri. In this study, 5-TTri biodegradation was enhanced through acclimation and nutrient supply. Activated sludge communities (ASC) were setup in nine subsequent ASC generations. While generation two showed a lag phase of five days without biodegradation, generations four to nine utilized 5-TTri right after inoculation, with biodegradation rates from 3.3 to 5.2 mg L−1 d−1. Additionally, centrifuged AS supernatant was used to simulate the nutrient conditions in wastewater. This sludge supernatant (SS) significantly enhanced biodegradation, resulting in removal rates ranging from 3.2 to 5.0 mg L−1 d−1 without acclimation while the control groups without SS observed lower rates of ⩽2.2 mg L−1 d−1.

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