Sludge size affects sorption of organic micropollutants in full-scale aerobic granular sludge systems

作者：Zhaolu Feng, Heike Schmitt, Mark C.M. van Loosdrecht, Nora B. Sutton · 发表于：Water Research · 年份：2024 · DOI：10.1016/j.watres.2024.122513 · 被引用次数：20 · 研究领域：Wastewater Treatment and Nitrogen Removal、Water Treatment and Disinfection、Pharmaceutical and Antibiotic Environmental Impacts

• Sorption of micropollutants at environmentally relevant concentrations in AGS. • Sorption (>40 %) for zwitterionic and six positively charged pharmaceuticals. • Granules have higher sorption capacity per g biomass than smaller sludge fractions. • Longer time to reach sorption equilibrium shows diffusion limitations in granules. • AGS has a similar or slightly higher sorption capacity than activated sludge. Aerobic granular sludge (AGS) is gaining popularity as an alternative to activated sludge for wastewater treatment. However, little information is available on AGS regarding the removal of organic micropollutants (OMPs) through sorption. In this study, the sorption behavior of 24 OMPs at environmentally relevant concentrations (1 μg/L) was investigated in six sludge fractions of varying sizes (>4 mm, 2–4 mm, 1–2 mm, 0.6–1 mm, 0.2–0.6 mm, and <0.2 mm) from a full-scale AGS reactor using batch experiments. Sorption was significant (removal efficiency >40 %) for 10 OMPs, including 4 zwitterionic and 6 positively charged pharmaceuticals, indicating the importance of electrostatic interaction for OMP sorption in AGS systems. Larger granules exhibited a higher sorption coefficient and capacity than smaller AGS fractions, probably due to increased extracellular polymeric substance content for larger granules. Equilibrium OMP sorption was only reached after 72 h in granules larger than 2 mm, indicating an effect of longer diffusion distance for OMPs into larger granules. Addition...