Pilot-scale insights into micropollutant removal in modified high-rate contact stabilization process treating...

This study investigated organic micropollutant (OMP) removal performance in a modified High-Rate Contact Stabilization (HiCS) process, where enhanced organic carbon retention and energy recovery constituted the underlying process design features. The fate of eleven OMPs was examined in a pilot-scale HiCS system operated in two modes, conventional and modified configurations, under sludge retention times (SRTs) of 0.5-2 days. Sorption and biotransformation were identified as the primary removal mechanisms based on mass balance analysis. Overall OMP removal efficiencies ranged from 24% to 82%, with no statistically significant differences between the two operational modes. However, the modified HiCS process exhibited enhanced sorption, indicating an improved capacity for pollutant retention in sludge. Investigation of SRT effects revealed that a shorter SRT (1 day) resulted in more efficient OMP removal. These results demonstrate that optimized HiCS operation can improve energy recovery while maintaining effective OMP removal under high-rate conditions.