Biodegradation of 2,4-Dichlorophenol by Mixed Culture in an Aerobic Fixed-Biofilm Process—Kinetic Model and Reactor Performance

Abstract

Abstract A mathematical model system for the kinetics of 2,4-dichlorophenol (2,4-DCP) was derived in a fixed-biofilm reactor using ceramic particles composed of dewatered sludge and fly ash as supporting media. Mechanisms in the kinetic model system included biodegradation of 2,4-DCP by attached and suspended biomasses as well as mass transport diffusion of 2,4-DCP. Batch kinetic tests were independently performed to determine biokinetic parameters of aerobic mixed culture. Molecular diffusion in biofilm (Df), film transfer coefficient (kf), and biofilm shear-loss coefficient (bs) were determined from the literature. Laboratory-scale column tests were conducted to validate the kinetic model system. In a steady-state condition, the removal efficiency for 2,4-DCP was ∼89%. Furthermore, the increase of the 2,4-DCP loading rate from 15 to 41 mg/(L·h) led to a constant removal efficiency of ∼90%. The model-predicted biofilm thickness reached up to 622 μm whereas suspended biomass in the effluent was 35 mg/L. E...