Air-water partitioning equilibrium of tetrahydrofuran in an activated sludge system

Abstract

This study evaluate the effect of liquid tetrahydrofuran (THF) concentration and biomass content on the THF air-water partitioning equilibrium for a simulated activated sludge system. The equilibrium of the partition at the air-water interface is given by a partitioning coefficient (p c) = C g*/C L, where C g* denotes the gaseous concentration in equilibrium with the aqueous THF concentration (C L). Variations of p c with C L in static pure water are evaluated, and high solubility of THF in water caused p c values to drop as the C L increased from 29.81 ± 0.16 to 297.75 ± 2.28 mg/L at a constant temperature of 27°C. Meanwhile, the hydrophilicity of THF in water induced abiomass effect, causing p c to increase in the activated sludge liquor. Due to the co-effect of liquid THF concentration and biomass content, the p c values of THF for the liquor of mixed liquid suspended solid (MLSS) concentration = 1220 ± 86 mg/L and THF C L = 242.91 ± 69.09 mg/L increased 22.5% compared to those in the pure agitated water. The biomass effect on p c of hydrophilic VOC increases the gaseous VOC emission rate from the activated sludge facilities.