Effects of Low-Concentration Perfluorooctane Sulfonate on Anaerobic Fermentation of Activated Sludge
The impact of low concentrations of perfluorooctane sulfonate (PFOS) on anaerobic fermentation of waste activated sludge (WAS) remains poorly understood. This study applied three PFOS levels (0.5, 1.0, and 4.5 μg/g TSS) to systematically evaluate effects on organic matter solubilization and nitrogen/phosphorus transformations. Monitoring of soluble chemical oxygen demand (SCOD), soluble protein, polysaccharides, NH4+-N, PO43--P, and three-dimensional excitation-emission matrix (3D-EEM) fluorescence revealed that PFOS significantly enhanced release of SCOD, protein, and polysaccharides. At 45 °C after 14 days with 4.5 μg/g TSS, SCOD peaked approximately 28% higher than control, indicating increased biodegradable organic matter accumulation. NH4+-N concentrations rose overall with fluctuations, while PO43--P release was inhibited, suggesting interference with nutrient transformation pathways. 3D-EEM analysis showed strengthened signals of aromatic proteins and microbial by-products, confirming matrix solubilization. These findings demonstrate a dual effect of low-level PFOS: initial promotion of organic matter release followed by potential inhibition of nutrient transformation. This study provides data support for understanding PFOS environmental behavior in anaerobic digestion and informs sludge resource utilization and risk assessment of emerging contaminants.