Enhancing Nicotine Biodegradation: Acclimation of Activated Sludge and Formation of Aerobic Granules for Improved Performance

M. Shahriari and G. Khayati

Abstract
This study investigates the adaptation of activated sludge for nicotine degradation by introducing glucose as a co-substrate. The acclimation process significantly improved nicotine biodegradability, leading to its complete degradation. In contrast, the non-acclimated sludge removed less than 10 % of nicotine over the same period. The acclimated system achieved effluent nicotine and COD concentrations of 0.95 mg L–1 and 31 mg L–1, respectively, with removal efficiencies of 99.81 % and 93.80 %. 16S rRNA analysis identified Bosea sp. and Paenarthrobacter sp. as potential nicotine-degrading bacteria under long-term acclimation. This study also examines the impact of hydraulic circulation on the formation of aerobic granule. In a 6-hour cycle, granules with diameters of 2–3 mm and high strength had formed, whereas longer cycles (12 and 24 hours) led to incomplete granulation. Increasing the nicotine concentration up to 1000 mg L–1 tested the granules’ degradation capability, achieving a COD removal efficiency of 91.02 %.

This work is licensed under a Creative Commons Attribution 4.0 International License

Keywords
acclimated activated sludge, aerobic activated sludge granule, tobacco biodegradation, nicotine biodegradation